Shelling out nearly 4000rs per month on an app is too costly. Mostly bloggers have other free options which they can use it or rather get it built on Freelancer where some developers are developing android app for blogs at Rs.5000 one time cost. Such at CodeCanyon, high quality app is available at 20$ one time cost for converting wordpress sites into native app. Check all such Apps on CodeCanyon
Hence, if you ask me, i would look for a one time payment option.
With your question regarding such model for restaurants, again such apps are available on Code selling platforms like CodeCanyon. However, i would suggest such would be beneficial for Schools. Admins can send school information or update on the panel which gets reflected automatically. Schools and parents communication rely a lot on Whatsapp these days. Also parents would keep the app installed to know information about their child on daily basis.