Grocery store kiosks can have training and standards issues and I say this as a kiosk barista/manager in training. It's very possible that you'll be taught a lot of recipes that aren't up to standard or won't be taught about clean plays or the customer support cycle. It's going to vary a lot depending on what your manager and store director are like but also it can be a lot more laid back and less stressful than working at a full stand alone Starbucks too

Lol, no, it isn't easy by most standards you might use. There is a steep learning curve to learn everything at first. If you have a good trainer and you absorb information easily, you can catch on quickly, but you won't be even close to done learning when your training time ends.

Your day-to-day quality will be largely dictated by your manager, coworkers, and how well you're staffed. If those things are all good, you may even kinda have fun. If all three are terrible, RIP.

Most customers are fine, a few are delightful, and a few could ruin your whole day if you let them.

It's pretty much like most jobs, but faster.