I think it has it's pros and cons. For pros- it might help ease out crowds later in day, especially the later they announce the hour increase. People may have made other plans such as dining reservations etc. This could also be seen as a con because now you have a dining reservation or other plans, but could have left the park later.
This was a trip we planned on a whim, and we plan on being super flexible. We are at CR so have luxury of coming and going at MK as we please. If anything the past year has taught us you can't always plan for things, and just live in the moment. Very "unDisney" mentality of trips past. But I'm looking forward to it. Hopefully we don't miss FP+ too much though, as I'm not sure my young kids would be as patient with long lines as we are. But again, going to use that as an opportunity to do things like find hidden mickeys, try some snacks we've always wanted to try, and ride the less popular but very much loved rides (by our family at least) ie. Tikki Room, Carousel of Progress etc. We are also excited to explore Tom Sawyer Island which we've never done! After a year + at home we will gladly take what we can get. Can't wait!