If he gets the nomination, should Joe Biden pledge to serve a single term in his acceptance speech?

I believe the only person to have ever done this was Teddy Roosevelt when running for re-election in 1904 (his 1st elected term, since he became President when McKinley was shot). TR won re-election in a landslide.

My thought is that it could play really well if Biden did this, especially if nothing about it leaked out and it was a surprise during his convention acceptance speech. He could say that he was going to focus for 4 years on re-establishing American institutions and foreign alliances in the wake of Trump and not on political considerations of getting re-elected. It could help alleviate concerns about his age if he made clear that he was only going to serve for one 4 year term.

I realize that lame ducks often have less political leverage, so there's that, but in terms of getting elected, I think it would be a positive. The public would have a clear choice between 4 more years of Trump or a 4 year single term of Biden. If it was a surprise announcement at the convention, it would get massive coverage and give him a huge bounce.