I'm confused. How are you not seeing a relationship? Many players who play these kinds of games want to collect every unit they possibly can, and when limited units come out, it's saddening to know that they may never come back (or at least not for another year). Especially when some of those units can be meta-changers or simply unique/strong picks (i.e. S!Camilla and S!Corrin, the only flying mages).

More limited content also means that players are more inclined to summon on these banners which they could be trying to save for when their favorite character comes out etc. Limited banners (when used in excess) are typically just used to lure players into either spending money or draining their F2P reserves of orbs so that the next release of limited units may lure players into spending money.

The fact that you're unfazed by the constant release of limited units means one of three things. You're a lucky F2P player who gets whatever they hope for, you spend money freely on the game (nothing wrong with that), or you simply play the game at a casual enough level that you don't care for these limited units.

If you still can't see the relationship between what I'm saying and a potential Halloween banner, then perhaps you are too unintelligent to continue this conversation with.