Agreed, I made the same mistake once by subbing on their website. Dealing with the eventual cancelation was an absolute pain.
Years later, I wanted to sub again, and this time I did it through the iOS app. Best decision ever, as now it just sits alongside my other App Store subscriptions and is easily cancelable in a single click.
Assuming they are both the same price this also speaks directly to NTY: people will give Apple a 30% cut just to not deal with their shitty practices.
I love this simple but excellent suggestion, thank you.