I think the other side of the coin that hasn't been mentioned yet is the salesperson (TT or TV). They are very busy trying to close the deal and won't take the time to point out the real limitations.
Someone already mentioned how you're more likely to have a safe (and comfortable) setup towing a boat that's at your rated max weight rather than a box non-aerodynamic box of a TT.
And going with a stronger TV isn't overkill if it helps eliminate "pucker" moments while you're on the road.
And I 100% agree with those who have pointed out the Payload limitations already.