Maximize Compatibility in Photoshop

My understanding is that if you check the Maximize Compatibility when you save a PSD it saves a hidden flattened layer in your file as a fallback for programs other than Photoshop that work with PSD files.

Is there any reason to do this? The last time I opened a PSD in something other than Photoshop, or at least other than something in the Adobe Suite, was Paint Shop Pro back before it was bought by Corel. I think it was version 3.

My only real concern would be opening a PSD from CS5 in an earlier version of Photoshop. And I'm thinking CS2 or CS3, not version 3 or anything like that.

I think mine's turned off. The main thing is don't choose "ask" or it'll drive you nuts.