It is always a worry, it is one of several reasons I don't do digital music, but so far the big players have been really good about it.I just flat out don't trust digital. Not at the time that the system is current but 5yrs or 10yrs down the road. I don't trust that the money I've spent won't just go down the drain if said company decides to shut down its network. If I buy a game, I want to be able to play it whenever I want. Just like my atari 7800, or sega master system or turbo grafix... all of which get used a lot to this day.
I just recently went to digital (within the last year) on my games and I am really enjoying the change.
The prompt to do this was an ever so slightly damaged disk for the latest version of Doom. Getting the game to start was just a nightmare. Once it did it was fine, but the 10-15 minutes of taking the disk in and out and restarting my Xbox just plain sucked.
The next game I purchased was Destiny 2. I ordered it a few days prior to launch from my phone. The game was installed, updated and ready to run automatically on launch day. If I want to play it at a friends house I just log in with my account and it is there. I can share the game with pretty much anyone I choose that has an Xbox Live account with a few clicks.
I was pretty much sold at that point. It is just so much easier without any tangible downside.
IMHO the benefits outweigh the risk. I am also not a big replayer of games so, for meat least, the risk is pretty minimal.