> I am sure within 10 years every professional mathematician will use formal proofs.

I'll take that bet. 1:1 odds, up to $50? Shall we say, every mathematician employed at an ivy league university math department (postdoc level or above) has published at least one paper which employs proof checking for at least some claim? (provided that they have published at all.) So I win if I can find at least one professor or postdoc employed at an ivy league university math department on August 18, 2029, who has published at least one mathematics paper, and who has not published any mathematics paper which contains any formal proof.

That's a much weaker claim than yours, so it ought to be pretty generous to you.