But using internal APIs are free. I can afford to use them since I don't mind having to update my usage of them / work around rate limiting.
I'd recommend pizza and beer at tech events instead (albeit the nutritional content of your diet could be more important than free food).
Even if they would have TOS for translate, pretty sure that’s unenforceable. Not unless hiding that page behind a paywall, or requiring a google account. Merely visiting a publicly available web page doesn’t create contractual relationship between end user and web server owner.
Even if they are, I have doubts that’s enforceable either. One doesn’t need to reverse engineer an API to consume that API, and it’s hard to find out who did the reverse engineering. The reverse engineering might be accomplished by someone else who’s not a Google’s Cloud customer, like an unrelated person answering a question on stackoverflow.com.