Thank you all for the good advice on both sides of the argument! I decided that I will spend the extra money and stay at the
Disneyland hotel. Mainly, because on our first day we get there around Noon and we don't plan to go to the parks that day, so the kids will really enjoy spending time at the pool and having a character meal at Goofy's kitchen while we relax and get ready for the next three days at the parks. Also, the MM perk will be nice for our days at the parks. I looked at the numbers a couple of times and decided that spending the extra money will not change any of our plans/spending for the rest of our trip, so I decided to go with it.