One of the simplest and most interesting observations for the Independent Private Values environment is that the standard auctions give the same revenue to the auctioneer on average. So, an auctioneer who is looking to maximize its expected revenue from an auction has no reason to pick one auction over the other.
To see the revenue equivalence let us consider the SPA and the FPA only, because as we mentioned earlier the SPA (resp., FPA) is strategically equivalent to EA (resp., DA).