What's the advantage in cutting down the search form?

[Mr Lucky]

I apologise if this is the wrong forum. This is mainly out of curiousity, but someone running this site has obviously gone to lengths to cut down the standard xenforo search form. e.g. https://www.speakev.com/threads/need-advice-on-how-to-sell-my-“place-in-line-“.155125/

So there is no posted by, or search everywhere/this thread etc.

Maybe there is a good reason, does anyone know?