1) SUBT/LOCU is easy, I really don't understand how you can possibly think cutting this out is an enormous time saver. Sure, on a big pull, or some such it could add a minute or two to the time it takes, but that's it. It saves very little time (at least with someone who has a clue what they're doing).
2) How do you know what you have? How do you know what to order? How do you know when you recv'd an item? Without Wacos, how do you FIFO appropriately? Without Wacos, how do you deal with open cases? The computers can be obnoxious, the system does run slow from time to time, but it keeps track of counts and that's VERY useful in the long run.
3) How do they ensure their on hands are correct? How do they ensure proper food safety in the meat freezer? This would, in theory, not be an issue if you were very selective in who was allowed to enter the coolers/freezers, but sometimes that's just not possible. PAs get sick, you get sick, vacations come, people quit, etc. If you can only trust 5 people to do things correctly, you're setting yourself up for a serious failure at some point.
Basically I see this as an excuse to be lazy and an invitation for wildly incorrect on hands... I suppose it would work OK at a very low volume store simply b/c there isn't enough merch. for things to get that messed up. So if it's low volume, you've got great PAs, someone in the backroom you trust not to mess anything up, and you're willing to take the risk of a massive screw up at some point... well go for it I suppose. Otherwise, there are a million ways this could get messed up and several of them could/should get you fired.