I have thought through this issue when I picked up a team mid-season. The advantage that the new owner gets if they don’t have to wait for 30 days is that they can cut anyone that might potentially be overpriced and then just put a high bid on them. That’s a pretty big advantage to adjust everyone on your team down to market price, at worst. If the 30 day rule is intact, then they have to weigh the value of owning an overpriced valuable player vs having the cap space, which is pretty essential to Otto.
For example, say the new owner owned Trout at $80. They can safely cut him and put in a bid for $90 and force the ‘market’ to bid him up. The downside for them is almost nothing and the upside is that teams in the league don’t properly push his value up and they get him at a discount. They can do that for anyone on their team that’s near market price and the rest of the league is forced to bid these guys up to ‘market’ value when they probably have minimal cap space. And they could set it up so all the auctions end within the same minute or two, which is a huge advantage for them because they’d likely be the only team with cap space that could win multiple auctions without endangering their cap situation. That could be pretty disruptive to a league.