As it stands right now, you get two days of perks for those things tied to your resort stay...EMH, parking, and the +X on FP+ and ADR reservations (ADRs used to be +10 no matter what...it's now +X, or the length of your stay).
One difference is that once you get the 60 day window for FP+, that window STAYS at 60 days, until the day you check out. So while you get a +X from your check-in date, you still get 60 days from the day in question for days after your resort stay.
Also as it stands right now, if you cancel your reservation you do NOT lose any FP+ or ADRs made. But in the case of FP+ you cannot make changes or additional FP+ until you are in the 30 day window.