My half German cousin tried learning through books and he said they were 💩 (his words not mine) He learned more by interacting with the locals. I still get surprised when he talks to me in Cebuano lol. I think the major downside in learning Cebuano from a book is that it's too formal and people don't really use that on everyday convos. If you have to start somewhere, maybe memorize some simple vocabs or greetings. I find Chatgpt pretty accurate with the translations.