Is using fs.writeFile() an acceptable replacement for a database for a fully Front-end website?

I have a fully developed and deployed front end website that is looking to have a way for users to voluntarily enter their name and email. To move the website to a server to host and implement a backend seems really difficult. Would it be possible for us fs.writeFile() to write to a file in the path? Would this run into security issues?

We don't mind if the names are public, we would make it a disclosure above the form. The main concern is that the website would be flagged as unsafe.