MS will support it & offers training. It can be managed easily by the same windows admins they have managing their AD infrastructure and desktop support.
I suppose office 365 is different. Smaller companies get a good bundle with Teams, Office, mail etc..
It's not perfect but it's by far the best mail server for internal Email.
Sure, you get the occasional bug like this, but it's less often than Microsoft screwing up the entire cloud.
Only if you have a large tenant (> 2000 mailboxes) at the time of transition, and even then there’s ways around it. I think if you were getting advice today, it would be to avoid hybrid as much as possible and find any other way to move over because of this stupid requirement.
Some people just modify AD attributes directly to get around having an on-prem Exchange install but that's not officially supported.
As an example, I worked at a healthcare org and it would have been $70,000 a year for hosted Outlook, but only $110,000 to buy the software outright and run it for ten years (700,000 - 110,000 is a big savings)