This thinking is not without parallel.
With an experienced game manager already rostered, KC made Mahomes a 1st round selection, and promptly sat him his rookie year. Smith did quite fine, and he ended up a valuable trade chip.
Sure Mahomes wasn't selected #1 overall, but Mayfield is no closer to NFL ready than Mahomes was, and Taylor's TD/pick ratio and elite legs suggest that he is capable of operating an offense now loaded with talent just fine. If he just does what he's been doing his entire career (he'll likely do better), odds are good the Browns will win games and Taylor will keep Mayfield comfortably marinating. Dorsey won't mind building Taylor's credibility, and hence trade value, for a season.
I don't see any better freebies than Taylor.