I'm working on a huge existing game dev project that is done in lua, and I can totally agree with you. The last project I did before this one was in, of all things, Typescript, so when I started to use lua I was quite weirded out by how simple it is... "What about type checking, async/await, list operations, refactoring, test coverage, and so on ?! How can I be sure that whatever I'm doing actually works?" But after just around 2 weeks on the project I started to realize that I basically already knew everything about the language and was already very productive on the project. Sure, I didn't have the same safety as with other languages, but I was churning out features and bug fixes, and constantly overestimating work.

Even though I don't think I would start a big project like this on such a simplistic language, I can't ignore the benefits it has. I guess at end of the day, you have to balance out not just how good and secure the code is, but also how quick it is to make changes to it and to onboard people to it.