It's expensive and time consuming, but to me it is worth it. You don't actually have to spend any time eating if you don't want to. You can just check in and get your band. I am paying for the garden viewing spot, not the food and drink. (The food and drink is not great, just acceptable.) On Tuesday Aug 13, I went to check in directly after the parade -- the line was long. I recommend you wait until that initial line clears out. I went into the Garden around 9:40 and secured my favorite spot -- against the rail that is around a bush all the way inside the garden. On Friday Aug 16th we didn't check into the dessert party until 9:15 and stayed until about 9:50. I didn't get my favorite spot, but I was just a few feet over, leaning on the rail along Main Street. People sat on the ground while waiting and were instructed to stand about 5 minutes before. On both days the garden was probably less than 50% full. You could have laid down and done snow angels if you were inclined. It is easy to get out of the Garden after the FW.
We spent a lot of time at the party, but you absolutely do not need to. I needed the rest and I am only interested in the parade, castle show, FW and non character photo ops. I have the time to "waste" at the party.