Yes, you can order at a register like normal. Some people like.mobile ordering, because it's sometimes faster but others prefer in person. Many spots don't even offer mobile ordering, esp at Epcot.
We do a mix. Often, we decide on a whim to eat somewhere and it's just as easy to order with a CM. Also, wait times w mobile ordering has been horrendous here lately for us. But occasionally, like last weekend when we were coming by Skyliner to Riviera on our way to HS, we mobile ordered dinner because we had time to on the ride there. And waittimes at Primo are consistently long IMO and it helped cut that down some.
You can just do it in your app if you want to check it out. Just don't finish your order or they'll charge you