The clock runs out. The temp mail service deletes the inbox. It is now "fully gone." Any password reset link or confirmation email sent after that is lost forever.
Enter (Temporary Email). These disposable addresses last for 10 minutes to a few hours. But are they safe? Should you use them for banking? Absolutely not. Here is the ultimate breakdown. gmail temp mail full
Summary
Did you know Gmail has a built-in trick for temporary aliases? You don't need a new account. The clock runs out
Gmail vs. Temp Mail: Why You Need Both (And When to Never Mix Them) gmail temp mail full