What's the difference between a compact router and a trim router?
IMHO - the name, grip, usage, power and accessories (or lack of).
The original laminate/palm/trim routers were 1 HP and under devices, made for one hand use - focused on trimming laminate and lacked any sort of accessory such as knobs (handles) or anything other than a simple fixed base.
Compact routers seem to be the recent incarnations with - increased power, > 1hp, various accessories such as different bases, the ability to use them as a simple "palm router" or add a plunge base or another type of base and extend the scope of work one can do with it.
My granddad always said, :As one door closes, another opens".
Wonderful man, terrible cabinet maker...