When he gave a Presidential speech he used one. When he was on the campaign trail he walked around on stage with a handheld mike (I have photos of him at events all the way back to 2007).

opposite. Hahaha! Seriously. He'll improve where he needs. I'm not worried.

No, I think what you see is what you get. He's been giving speeches for going on 50 years, he doesn't need to get more experience. Heck, he's run for president twice before. Plus he's at an age where these facilities tend to, if anything, get worse rather than better.
I don't mean this as a comment on whether his speaking abilities are or are not good enough to win the nomination... only that, whatever they are, I doubt they'll get better.

At 0:25: "He's looking, they're bad, because quote, they're, he's looking to tear down the constraints the courts have put on him." I went to the advance release of the remarks to see what it was he was trying to say, but assuming that was what he was reading, I think he intentionally uses the teleprompter only as a rough guide, he improvises a lot. Sometimes successfully, sometimes not.

(The official text is at https://www.cnn.com/2019/06/11/politics/joe-biden-iowa-remarks/index.html )

He also doesn't enunciate very well, slurring words. Independence became indepence (0:10), Mexican became Mexan (0:20), and so on. A really bad one at 1:41, listen to him try to say "repudiate."

He's certainly not the kind of dynamic, inspirational speaker that Obama was, but that's a high bar.