Is “early accepting” PhD offers normal now ?

Quick question for US PhD applicants (especially internationals):

I’ve noticed some people accepting/rejecting PhD offers very quickly after receiving them (even in early February). Is this a new “early acceptance” trend? Or are these usually return offers from previous labs/target PIs? Or mainly to start the visa process ASAP?

When I applied, most people waited for visit days (after talking to different professors) to decide. Has the process changed that much?