You can think about it like a smarter disposable email service that also generates a password for you (and with a better UI).
The cool thing is that unlike disposable email services, it also saves the login info for you for later use.
I made it as a fun side project to scratch my own itch - I like checking out new products, and I was ticked off that to even begin to try something out, you need to register for an account.
The problem I had with disposable email services was that you lost access to your account, and you couldn't keep track of all the different services you signed up for (without polluting your password manager).
Happy to answer questions, and looking forward to engaging with the HN community - I love this place!