Dr Drang talking through subscription based apps, with regard to Ulysses:

If I were interested in Ulysses but hadn’t yet given it a try, I might see the subscription service as a positive. Ulysses used to cost $45 for the Mac and $25 for iOS. Now I could give both versions a good, solid two-month trial for $10. If they don’t fit my way of working, I walk away $60 ahead and knowing exactly why I shouldn’t continue the subscription. This is the sort of in-depth knowledge you don’t typically get with the common 7- or 14-day trials.

This is a must read post for some good old logic.