I was speaking from experience selling single-fee end-user Windows apps for about a decade. Trials are basically a must as virtually no one would pre-buy to test.

Perhaps on Macs it's different, or maybe it's due to your price point, but still your approach automatically drives away a large swath of potential, but cautious buyers, or those who don't want to be bothered by the refund process. Your pitch is "here is some good stuff, and here are the hurdles if you want to test it".