François Yves Le Gal wrote:
All pro studios I'm familiar with have a very wide assortment of valve
mics, vintage or recent, which are put to very good use for a very large
number of recordings.

Define what they are particularly suited for?

Anything and everything. Vocals, guitars (both electric and acoustic),
strings, you name it.

It's probably fair to say that the majority of successful vocal recordings
are made through an expensive valve mic. (And, frequently, from there into
a -- digital -- SSL desk and edited -- digitally -- in ProTools.)

But in common use?

Yup, every day, in all the big studios.

Valve power amps are common too, and valve processors and mic channels even
more so. All-valve desks are popular too. There's even groove machines (drum
machine + synth + sampler) with valves these days.

Just a point of fact...