Palo is a wonderful place to enjoy a 4-course meal -- appetizer, salad, entree, and dessert. You might also want to have drink before dinner and some wine with dinner. The way to enjoy a meal like that is not to arrive when you've already eaten. In fact, we avoided any sort of afternoon snack to make sure we could enjoy our dinner courses.
Yes, there are people on this board who have done exactly as you're suggesting. You may even get some replies saying that it's wonderful idea. I would disagree. The only justification I could see would be for those cases where parents want to accompany their young children to the early seating dinner and then go to Palo later (while the cjildren go to their club); even in such a case, I would avoid eating at the first dinner.
You can't experience everything that the cruise has to offer. It's worth skipping one of the regular dinners to go to Palo.
Also, if you go to the regular dinner and to a late dinner at Palo, you'll miss your evening show in the Walt Disney Theatre. In my opinion, "dinner and a show" makes for a nicer evening than "dinner and another dinner."