What? A TE? Hear me out here. Yes, the Steelers already have an ascending TE in Pat Freiermuth and shouldn't feel the need to take one in the 1st Round. Yes, the Steelers have weaker positions that they could address in the Draft (CB, DL, OT), but think about it for a second.
Let's start off with the other positions of "need" that the Steelers have.
At worst, this position group will not be worse than last season. On the whole, Patrick Peterson will probably be an upgrade over Cam Sutton for at least this year. Sure, you would like them to Draft a CB to develop behind him, but you don't necessarily need to take one at #17 to accomplish that. Would it be nice to get JPJ, Witherspoon, Gonzalez? Absolutely, but this Draft is littered with talent at CB that you can still get a high end guy that would go in the 1st in most Drafts at #32. The Steelers don't need to address CB at #17.
Another option the Steelers could have at #17 is DL. Maybe Jalen Carter falls there, but I don't see Tomlin taking him if he does. They already got bit by a Georgia star falling from grace to #17 and paid for it when they took Jarvis Jones based on the hype before his poor testing. Other than that, there aren't really any Defensive Linemen I would be happy with them taking at #17. It would be reaching, especially for a NT, which is their biggest need at that spot right now.
This is where my argument starts to fall apart a little and I acknowledge it. Chucks is solid at RT, but Dan Moore has shown that he isn't an NFL left tackle. Is that all his fault? Maybe, maybe not. We know Kevin Dotson hasn't been the greatest next to him either and Isaac Seumalo is a definite upgrade over Dotson. Dotson was also largely responsible for Kenny Pickett's 2 concussions last year with missed assignments. Maybe a new face next to Moore can give him a little bit of an edge he didn't have the last couple years. At worst, the OL will probably be better than it was last year. It would be nice to have an OT like Jones, Johnson Jr., and Skoronski, but there is no guarantee that either of those 3 guys will be available at #17, Someone else like Dawand Jones, Anton Harrison, or Darnell Wright could be had at #32 or even at #49.
That brings us to Michael Mayer at the TE spot. There is some definite depth concerns behind Freiermuth, who has had a well documented injury history throughout his career. The first reason I would be very happy if they took Mayer is that it gives them insurance in case Freiermuth misses any extended time.
An additional, even bigger reason that Mayer could help them is that by far, the biggest thing that held them back from making the playoffs was their ability (or lack thereof) to score points in the red zone. Mayer has a ton of tape of being a clutch red zone threat and matchup nightmare. That's the biggest thing that jumps out on tape about him. He doesn't stretch the field, but he is clutch and a near elite possession receiver.
A final reason why Mayer's addition would help this Offense out is that it makes WR depth even less of a concern. Mayer is more of a traditional inline TE than Pat Freiermuth. Not saying that Freiermuth can't play that spot, but he is more lean and athletic and would be better served as being a big slot receiver, where he was one of the most effective slot TEs in the NFL. It would also keep him healthier by not being in the trenches as much, which Mayer playing the blocking, inline TE role. The Steelers also ran most effectively down the stretch out of 2 TE sets, so Mayer fits right into their plans there. He helps out the Offensive Line and accelerates Kenny Pickett's development as a QB, having another safety net when nothing is available downfield.
tl;dr The Steelers need to score more points in the redzone more than any other need on the roster. Mayer addresses that need more than any other single player in the Draft. He helps out or OL and WR depth as well by letting Freiermuth play a big slot.