Anything that could possibly make the first post experience worse is bad for the site.

I've said it before: a rudimentary spamfilter is relatively trivial to implement (in anything) and will block 95% of spam posts/users, without ever being used unintentionally. I've been around here a while and have never in my life seen a spam post that did not follow the cookie-cutter sequence of a brand new account posting a verbose off topic post filled with links to dropshipping websites. Every aspect of these spam posts are identifiable and preventable.