Not quit sure where battery life is comming from, thats not my argument. To restate and also better phrase my argument: Stored energy is the better measure for consumers for the quantification of the battery size in a consumer device compared to ~~Ah~~ stored charge.

Now i can cross compare devices based on that and do not have to worry about the Voltage of the battery of any other devices.

Please state the calculation that you would use to "determine how often you have to recharge" that is valid for Wh and not for Ah.

I never claimed that this is possible. I wrote "can recharge" not 'have to". I am referring to devices like a power bank which i can calculate with a simple:

powerbank has 100Wh and phone has 25Wh so 100/25=4 -> i can recharge my phone 4 times using that powerbank.