The minimum and maximum "Current Bid" options could be more useful if there was a way to choose to ignore reserve prices, the majority* of which are at levels that won't be met.
To give an example, say I'd like to be able to search for players with a minimum current bid of $3M. If I do that right now, the 24th player returned is the first one with an actual bid. The first 23 are just listings with reserve prices of >= $3M and no real bids.
* No proof, just my estimate.