Yellow definitely has a place, and it is also dependent on the film.
And of course yellow only eats about one to half a stop.
Look through the filter to get a reasonable idea of how it will affect the scene.
I find that yellow often has a surprisingly big effect.
The complementary colour to deep sky blue is not red or orange, but rather deep yellow.
Yellow makes the blue sky just that more distinct from the clouds in a contrasty exposure, that it's useable, without gymnastics and too much grain.
It also makes skin look more dainty, without bleaching out red lips, or attenuating rosy cheeks, or in the case of dark skinned persons, making them look lighter than natural (red can do that).
R/O can also definitely be too much on landscape stuff and where you want to retain shadow detail (shadows are mostly blueish).
R/O also rarely gives the much vaunted dramatic dark sky effect.
You have to be lucky with moisture levels and also probably use a polariser on top.
The best way to get dark skyes is to use IR film.
Green/yellow can be a nice compromise to not blacken out the foliage too much.
One often overlooked option is the nice brown urine sample coloured filter (not merely warming).
On B&W it has some deep yellow effect plus some green pass.
