x265: Specifying --frames ?

[Forteen88]

I wonder, is it worth it to specify --frames in x265? I mean, does it improve picture-quality? Judging by the x265-documentation-guide, setting it seems to improve picture-quality,

--frames <integer>
The number of frames intended to be encoded. It may be left unspecified, but when it is specified rate control can make use of this information. It is also used to determine if an encode is actually a stillpicture profile encode (single frame)

[Boulder]

I specify it just to see the ETA of an encode. I never thought of any other effects it may have.

[DJATOM]

--frames is also useful if you want to encode only few frames from input.