Jayrok
Footballguy
Different ways to look at this. If he stays in the 2020 draft, he could drop due to concerns. Would he rather play for Cincy/Miami, or what if he could drop to a decent team that needs a good QB. Would he rather play for cincy or, say, the Chargers who have players in place already. If he plays for Cincy and has pressure to perform right away (after teams watch Watson, Murray and L. Jackson do so well so early) he may have a hard time living up to expectations (see: Rosen, Darnold, Mayfield) and be caught in a never ending rut... like Cincy.
If he lands on a team that already has good parts in place (like LAC), or even on a team that has a good but aging QB (Saints, GB, Panthers, NE) he could sit and learn for a season or two (like Aaron Rodgers did).
The big money is in the 2nd contract, not necessarily the rookie deal. If he is drafted by the Bengals his rookie contract may be the only decent one he sees.
The injury might could be the best thing to have happened to him, assuming he makes a full recovery. The top of the 2021 draft is also going to be a crap shoot with the same familiar suspects. If he lands on a good team in 2020 he can avoid the noid of those crappy teams altogether.