Strikers often score in batches to become the new guy everyone talks about, only to fall back down to earth when they recede to their normal level (eg. Piatek's start with Genoa, or Jovic's 5 goal game). With that in mind, those players you mentioned haven't scored goals consistently enough for a long enough period to say that they're the real deal. Conversely, Werner has continued scoring at an excellent rate since his breakout season in 2016/17, and is thus also Germany's main striker. Big difference.They were just names out I was throwing out lazily, I did say it's not for me to say specifically. Those players are have records similar or better to Werner in recent years.
If Werner can be bought on the cheap he's worth consideration. My main point was that he's not good enough to break the bank for and that I'd stick by. The fact that he's had to be substituted before due to a noisy stadium isn't ideal either. I'm also unsure how you'd criticise Belotti for not doing enough in the buildup but then go so hard in for Werner, I don't think Werner does any of the stuff Firmino does either but Belotti is a decent target man.
As for the noise, I don't think the noise issue is something to get worried about. Even if he does have a minor issue he isn't going to be playing against Besiktas away very often.
The reason I'd be more for Werner is because he's excelled in sides that have played pressing football off the ball, and quick passing and counterattacking with it. He might not be as tenacious as Firmino off the ball (no one is), but he has a proven track-record in pressing sides.
Conversely, as you said Belotti is more of a target man who needs to be supplied with the ball in totally different style to what we play to be successful.