They do, and they were quite common at one time. One other advantage they
have is that they lack separate windings providing continuous power to
the
filaments in the tubes so the total power consumption is several watts
lower.

The power savings is perhaps 1 watt per lamp and perhaps another watt
in the ballast. The downside is much shorter lamp life. Rapid Start
ballasts are by far the most common type of EM ballast use for 4-foot
fluorescent lamps in the US.



From what I've read, it's more like 3-6 watts per lamp, which if you're
talking 500 lamps in a decent sized building can be somewhat significant. I
haven't looked at what it does to lamp life, but instant start is the worst
for that. It gets confusing too that most commercial or industrial types are
specified at 10 hours per start, while residential lamps are rated for 3
hours per start. Lifespan drops dramatically with more frequent starting
cycles.