I see both sides. I think his point is that people can easily spend 20 dollars/euros/pounds a week in petty cash on coffee, snacks etc. If you'd half those costs for two weeks you have your sync money.
On the other hand 20 dollars is a steep price when it comes to mobile applications.
Maybe a breakdown of associated costs from LJ would help justify his current pricing. I'm assuming it's based on his experiences with Sync for Reddit.
I was a Sync ultra subscriber and I thought it was a bit steep but on the other hand I loved the app and wanted to support him as I understood that a one time cost of 5 dollars for Sync pro wasn't a realistic pricing model either.
At the end of the day if the Sync for Lemmy ad free cost is realistic for both his costs yet affordable for the average consumer then I don't mind if Ultra is a bit steeper.
This feels like a near 1 to 1 copy of the Sync for Reddit app. And I mean that in a very positive way. Sync got me into Reddit, and I think it can definitely do the same for lemmy. I'm very excited to give this a try.