Those charts are such nonsense. As I said, we've gotten same day FP+ for so many of these rides waaaaay past when the chart says they should be "gone". With people changing their plans constantly, new FP+ come and go continuously. I'll give you a good example. Christmas week...I don't remember the exact date, I want to say it was around Dec 29th or 30th, as I remember it was toward the end of our trip. It's the busiest week of the year. MK was incredibly busy. We got on Buzz, Splash, BTMRR. I then got Space Mountain for the kids literally 10 minutes in advance, and Pooh for DW and I. I love SM, but DW won't ride, and since we have 3 kids, I let them go on their own and take a car together while I spent time with DW...ain't I nice.
We got off the ride first and were sitting outside waiting for the kids. I was just playing around with MDE and guess what...I got them SM again literally 5 minutes ahead. So they got off and went right back on. No, I am NOT saying this WILL happen to everyone, all the time. But we have had tremendous success like this, even in the busiest time of the year. Make no mistake, the week of Christmas to New Years was far harder than any other time we've been, but it was still possible. Summer is pretty much a breeze for anything except FoP (maybe that will change this year??).
Yes, it takes a lot of refreshing. I've said in many other posts that I am not a person to be face into my phone. Outside of WDW, I use my phone less than 99.9% of people. I don't even text, I've never sent a text in my life...seriously. Nor do I do any form of social media. However, the MDE app is just worth it to use. And, IMO, it's such a simple, mindless thing to do that it doesn't take away from family talking time. I do it while we're standing in line talking as a family, as it takes very little attention to do. In fact, my kids think it's a fun game to see what comes up, kind of like spinning a prize wheel.
I use an Android phone. I don't use WDW wifi, I use my cell data, much faster.