At 6’0” even, Tagovailoa is considered borderline short in the NFL, where teams prefer their hurlers to be over 6’3” (at least) and give preference to those who fit this archetype over those up and comers who do not.
The reason height benefits an NFL quarterback is that the taller he is, the better he can see and throw over the raised and outstretched hands of the giant defensive linemen who will be relentlessly pursuing and descending upon him throughout every game.