They're nearly the same thing, by pretending they're going to impeach Biden they make it seem impeachments are no big deal and are boring procedural matters, providing cover to Trump by minimizing his. They don't even need to bring it to a vote if they can get enough media coverage "investigating" the current McGuffin of the week.
This is about starting an inquiry. The Republicans don't have the votes to start. Plenty of Republicans will not vote for an inquiry. McCarthy tried starting without a vote today.