Bill likes to acquire pitchers with 65% of their salary already paid during the season by their trade partner. It would be easy to call that being cheap, but it also allows him to debut minors pitching in the first 65%, without being blocked.
A secondary benefit BB first mentioned is avoiding injuries during the 65% stage, because you will only be acquiring healthy and ready to go pitchers at the deadline.
And my favorite, do you want to draft in the early twenties every season, or late twenties, every round? If you keep a low hanging fruit cheapo bullpen, you’ll never see a late twenties pick, and will also avoid/pocket salaries of better relievers.