Can HTTPS ngrok tunnels be a safe way to run a production server?

If I use ngrok with HTTPS tunnels and a password, is it a safe way to run a production server from my computer?

I have been experimenting with this for a few days, and I noticed when paired with Voila (Jupyter Notebook Dashboard framework), a single HTTPS tunnel can easily handle the number of users I would see in a typical day. This seems to be a highly cost effective way to run a web application, but I imagine there is some safety issue I'm not aware of.

Thanks!