Is there any use in keeping pokemon such as butterfree, beedrill, pidgeot, raticate, etc.?

I use them 1x to prestige and dump them unless they have great IVs and perfect move set.

I keep one with good IVs and moves for collection, but dump the rest.

keep atleast the ones with good ivs just in case breeding takes into consideration the iv

Beedrill eventually gets a mega evolution with a considerably higher attack stat than Dragonite.

Might want to keep a good one for that.