So a web app is easier for you, but aren't you really just transferring the cost to your users in the form of battery and data consumption?
Would it be, in a way, pushing costs onto users? potentially. But, it's a matter of shipping something that works at the loss of some battery and data usage (minimal) or spending 6 months to a year learning and developing a native app which is more efficient for end users. But both approaches are subject to market validation - one lets you reach validation quickly, the other requires quite a detour.
So, I'd rather not throw away all that time. If I can get notifications that work, even if only checked every 10 minutes vs. instant, I would be happy. Then, if there is market fit and proper demand, I can likely afford the time/money to build out a native experience.