Hollow body frogs are… wait for it… hollow. So unlike a crankbait, jerkbait or treble-hooked topwater plug, they tend to hold residual water once you’re done fishing with them. The legs hold water and unless you go crazy squeezing the water out of the bodies when you’re done fishing, there will be water inside of most frogs as well.
Once you put these frogs in storage and knock ’em around in the boat for a while, the water will eventually seep out and pool in the bottom of a traditional tackle tray. I have dealt with a lot of rust issues in the past due to this.
The cups of the Crank Bank actually have two drainage holes on the bottom which, in my opinion, is an awesome feature for frog storage. I can’t tell you how many times I’ve picked a frog out of a tackle tray only to have the legs disintegrate from dry rot. I’m definitely not smart enough to know, but I imagine residual moisture has something to do with that issue.