Why do you think that their free tier is not great? AFAIK, it works like any other free tier email service but with encryption. Though it does have a limited storage space (which has increased recently). Anyone who would need more than that & has chosen to use PM probably also understands the cost of free products available & will be willing to get paid service
Disclaimer - I am a paid PM user (converted from free tier after using it for few years)
Why do you think that their free tier is not great? AFAIK, it works like any other free tier email service but with encryption. Though it does have a limited storage space (which has increased recently). Anyone who would need more than that & has chosen to use PM probably also understands the cost of free products available & will be willing to get paid service
Disclaimer - I am a paid PM user (converted from free tier after using it for few years)