Attract MORE UPGRADES and NEW USERS by guaranteeing no runaway billing when someone dies or becomes incapacitated.

A Proton USP: Guarantee PRIVACY DURING LIFE (as now) AND NO RISK OF BILLING AFTER DEATH OR INCAPACITY. Avoid the executors of someone's estate having to (a) discover that the deceased has a Proton account, (b) find out the user name and password, (c) contact Proton with that information, (d) deal with all the paperwork. OFFER the ability to pay for upgrades and new accounts by buying credits. Services are terminated and billing stops when the credits run out. This model is used by some competitors (for example, Posteo). This would ATTRACT NEW USERS and MORE UPGRADES. The only reason I do not upgrade is because that payment possibility is not available at present. It is not a marginal (edge) issue because IT AFFECTS EACH AND EVERY USER because EVERYONE dies and some of them even when still alive will become incapacitated. The credits approach allows privacy to be guaranteed without storing up potential problems for executors of the estate or people who have to take over a user's finances because the user has become unable to deal with them themselves.