Sure it's easy to do. Assuming you know the parks, you know exactly what you want, where you want it from, and have planned in advance to get it. I don't mind mobile ordering at the resorts to be honest. It's way more of a pain in the parks when we are walking, and the kids smell something and start saying they are hungry. "Here, lets get my phone out, stop and sit for a while, and we can spend 5 minutes deciding what we all want in all the menus. Then we can eat in 20-30 minutes."
Let me also state I don't hate it, nor do I think it has no value in it. BUT, the ENTIRE point was that it has not increased capacity. I don't have insider knowledge, but I'd be willing to bet that when the QS places were designed, they knew what capacity the kitchen could serve, and built the number of registers to coincide with it. Mobile ordering wasn't some great plan to increase the capacity of the food in the park, it was designed so they could have less people being paid to work registers.