DonM The flip side of that strategy is that you have to use a precious draft pick on a guy who is less likely than most to amount to much.
The payoff is potentially that much larger, though - it's already an advantage to have a starting QB on a rookie contract when that player is an early first-rounder (CJ Stroud has a 4-year, $36.3m contract with a $6.6m cap number this year, for example), so it's even more of an edge when it's a late-round rookie contract paying about $1m per year.
Late-round draft picks aren't worth all that much, particularly when teams get additional picks through the compensatory pick system - a 5th or 6th-round pick is, on average, a bit more valuable than a rookie free agent, but not all that much.