Isnt the main disadvatage of TCP over UDP, overhead, present only in unreliable connections? Afaik, when there is no loss or congestion, TCPs roundtrip or order

Isnt the main disadvatage of TCP over UDP, overhead, present only in unreliable connections? Afaik, when there is no loss or congestion, TCPs roundtrip or ordering does not cause significant delay. So how relevant are the benefits you listed (faster development, multiplexing, congestion control) for residental end points? I am sceptical.