I'm young, but I am not really a big fan of electronic tickets. I find it especially annoying when I sit in good seats and the ushers constantly pester to check my ticket. Sure let me pull my phone out of my pocket, unlock it, find the app, let it load for 5 hours, and then show you. It is a bit of a pain. I have never really had huge issues getting in, but a nice solid sun will make it hard to read for the scanner and as always who knows when your phone will act up or even worse...the app be down. One time StubHub's ticket shower thingy screen was down. Thankfully it got back up and running before the Brewers gates ever opened, but some people going to a basketball game or something couldn't get in right away and they were not very happy about it.