More valuable than buying the extra cheap WW innings (which are of terrible quality) is pushing back the usage of your higher quality pitchers. If you throw your 200k or AAA starters in your first few games, you’re playing with house’s money as far as your other pitchers’ stamina.
Very simply put, a SP allotted 324 IP can effectively be used an avg of no more than 2 IP per team game played. You start him game 1 and he goes 7 IP, he’s already behind the 8 ball by his next start in game 4. If his first start is that game 4, he’s ahead of the curve. So by throwing a scrub early, you can maximize your real starter’s usage, be it rate return your or not worrying as much about pitch counts.
I use a slightly different approach, where I stretch my pitch counts the first turn through the rotation, THEN throw the scrub. This helps keep my RELIEVERS ahead of the curve, which I find more difficult to manage than SP. SP, as a function of total IP, quickly get back to a usable 90%+ stamina, if they’re stretched an extra inning or two ahead of their allotted rate. Those extra innings are murder for a 40 ip reliever.