If you think that you are perfectly safe when you use a VPN, then you don’t understand how they work.
A VPN protects your data from your phone, tablet or laptop up to the VPN provider. So it protects the data going through an unsecured hotspot. But it provides zero protection beyond the VPN provider.
But it gets worse:
You are entrusting all of your data to the VPN provider. The VPN provider knows who you are. They probably have your credit card, your billing address, and all of the data you send. This means that they have your email credentials, including your password.
What if the bad guys happened to be the VPN provider? That would be a very very bad thing.
So use care and discretion when choosing a VPN provider.