SBMV is a typical "spork" (spoon and fork at the same end). None of them work good.
The efficiency is too low for the street lighting and the CRI is too poor for the indoor lighting.
They call them "blend discharge lamps" in Czech, which is pretty misleading.

According to the Philips charts, the start-up power is approx. 140% of the final power, when completely warmed up. ("Ila" /not sure, what it is/ is 130%.) Thus, the current changes quite significantly.

What is the temperature of the tungsten filament during the warm-up process? Is it overheated at the beginning or not fully glowing, when the MV is completely lit?
Thanks.

It§s called "mixed light" in English and other languages as well, it does mean the overall light is a mix between the Planckian radiation of an incandescent filament wioth the discharge light from the arctube.
The main purpose was to offer, in the 1930's, something of better quality light than the bare medium pressure mercury, but with higher efficacy and mainly longer life than the incandescent lamp. And i allowed the use of at that time novel mercury discharge within incandescent fixtures.
And since then it served about the same purpose: Better efficacy than (mainly a long life) incandescent, yet no need for any special gear.

The filament run hotter during startup than usual for an incandescent, but the whole design count on the fact, the lamp won't spend so much time in that state, so the overall degradation will be still manageable.
At full power the filament operates usually about 2600..2700K, but the main efficacy loss compare to the incandescent lamps (of the filament only, exclude the arctube) is caused by the rather low pressure gas fill and quite long shape of that filament.

When comparing to the incandescents, you should take into account, the SBMV's are designed for life of 8000hours and above. WIth that life rating, an incandescent wont be even half of that efficacy...

Of course, the magnetic ballasted discharge is more than twice as efficient (e.g. an MV), but need quite heavy gear, what was is a complication in some cases.

I would think the CRI would be just fine for indoor lighting. A typical DX coated lamp has a CRI of 45 to 50, and the incandescent ballast would bring that up further. A warm white fluorescent has a CRI of 52, so an SBMV/DX should be just fine. I'm not sure if it's true, but I once read that they're quite popular for indoor lighting in Japan.

To add some more numbers to what Medved said, the incandescent filament in a 120V SBMV is rated for about 80 volts (according to what information I have found on here). Upon power-up, the arc voltage is only 10 or 20 volts, so the filament is doing 100 or 110 volts. Then once the arc tube has fully warmed up, it's doing probably 60 volts, so the filament is also doing 60.

If we assume the filament has been designed to last the rated life of 8000 hours at 60 volts, that would mean it would last around 1280 hours at its nominal 80 volts*, and only 100 to 200 hours at the high voltage it gets when the lamp is first turned on.

* Most 130V incandescent light bulbs are rated for 2.5x their rated life on 120V, so I've assumed this rule holds for SBMV filaments, and across a range of voltages.

The CRI of the Osram HWL 160W and the Philips ML 160W is about Ra8=65, And the color is about 3500K, warmer and better than that of regular /DX mercury lamps. Light output is similar to a 200W incandescent lamp when operating at full regime.

I would think the CRI would be just fine for indoor lighting. A typical DX coated lamp has a CRI of 45 to 50, and the incandescent ballast would bring that up further. A warm white fluorescent has a CRI of 52, so an SBMV/DX should be just fine. I'm not sure if it's true, but I once read that they're quite popular for indoor lighting in Japan.

Thanks to all. I have no personal experience with SBMVs, but I'm thinking of buying one before it becomes illegal.
What I heard of them is that when MV warms-up fully, it dominates in the way that the contribution of the incandescent is barely noticeable.
And the spectrum chart included in the zip file on the ML 160W E27 220-230V SG 1CT specification at philips.com does not show radically better spectrum when compared to HPL-N 80W/542 E27 SG 1SL.
But as I said, I have no personal experience. Maybe, I'll be surprised.

The incandescent is continuum, so even when it appear low, it's total radiated power is not that negligible, just because it occupy wide part of the spectrum. The discharge and phosphor peaks are high, but because they are narrow, their total power is not that large.
But it is true, the incandescent light does not add as much lumens, but that is just because the main power of that incandescent light is radiated in the red area, where even rather high radiated power dcoes not add so much lumens. But it is very important in the color: It improves the deep red rendering...