If you add "lemmy" to the end like you would add for reddit based results you should be able to search just fine. There's just not enough content or awareness yet to matter.
Perhaps not enough content yet. I'm not getting any positive hits on Bing or Brave search.
One concern about federation is that search engines could potentially (and likely) dilute results because they appear to be coming from different sites and URLs.
It's all text, and nothing particular locks content away from crawlers from what I see. There's no reason that web search engines won't treat lemmy instances the same as Reddit. I think it will just take a little time while new, relevant content is generated and placed here.