Creativity ebbs and flows, and needing to pay monthly for writing software is exorbitant. Charge once, don't require registration. Writing is hard enough without all these additional steps and overhead cluttering the mind and day-to-day, week-to-week creative process. Monthly fees are obnoxious, and forces a lot of overhead (payments, regular usage, long-term accumulation, online billing, etc.) for what's already a very difficult process.
It runs counter to the writing workflow. Fast shouldn't be the goal: quality, long-lasting content is.
(1.) Requires signup or registration. (2.) No local client app in App Store. (3.) It should be a one-time fee rather than a monthly cost.