I think the new system is great. Never have to worry about getting to a tackle store during their hours. Print as many copies as you want and keep them everywhere (wallet, boat, truck, with your gear, etc.)

I haven't bought my license in a tackle shop since the online system began.

I keep my last store-bought license as a memento at my bar.

And like suggested, keep a copy on your phone (either a photo, or the actual receipt file as an email attachment). Although an electronic copy may not be "legal," I'd bet it's up to the officer's discretion if he looks up your Conservation ID number and sees that you're legit, he'll send you on your merry way.