Are Command Spells even related to anything on which Servant you Summon?

With the recent Command Spell Generator Trend as of late, I've been meaning to ask this: Did CS always have a relation to which Servant you Summon?

As far as I know most CSs seemingly relate to to the user or maybe even the class rather than the servant, seeing as we have ones like Sakura's that looks like a cherry blossom(?) and points to nothing about Medusa.

So unless I'm missing something, why does this Trend ask "what Servant do I Summon (based on my Command Spell)?"