Seedling directly into their final home

Okay, let me preface this with I am in South Florida, so I can put plants out at anytime...

I've started some seeds, and the seedlings have 2-3 sets of true leaves. I've been hardening them off/setting them out in the sun for a couple weeks now. These particular plants will be going into 3 gallon SWC's. I was going to first transplant them into Solo cups, and let them grow a bit more, when I thought...why?

Is there any reason why I shouldn't transplant the seedlings directly into their final home/container. The only thing I can think of would be good hard rain might play havoc with the young plants, but I think I can pretty much protect them from that.

Thanks for any input...

Mike