Facebook is not the default everywhere. WhatsApp, Telegram, LINE, WeChat, and KakaoTalk win whole countries. A map of feeds vs messengers - and what that means if you sell across borders.
Shop, courses, bookings, tickets, subscriptions, delivery, utilities - seven payment-bot shapes, when to use a chat bot vs a Mini App, and what a production checkout looks like.
A concrete payment-bot example for educators: catalog of courses, invoice, webhook, then a private channel invite, files, or a lesson Mini App. Installments and Telegram Stars included.
A payment-bot example for appointment businesses: calendar in a Mini App, 20-50% deposit, reminders, reschedule rules. Empty slots stop being free options held by people who never show up.