It should be perfectly fine if people want to pay with personal information, as long that personal information has zero social costs.
A prime example is sharing information about DNA since that has a social impact on relatives. Less obvious problem would be people in a position of social position, like say a judge or jury, since access to personal information in that situation provide unfair position of power in society. It also is a problem with voting, since access to voters personal information has a high risk of influence elections.
To take a more direct example, if you are paying your email provider with data, then you are also selling the information of anyone who send their emails to you. The sender is in an impossible position in that they can't know who the email provider is of a recipient (email forwarding is a thing), so the social cost is on the recipient if they sell the information.
A prime example is sharing information about DNA since that has a social impact on relatives. Less obvious problem would be people in a position of social position, like say a judge or jury, since access to personal information in that situation provide unfair position of power in society. It also is a problem with voting, since access to voters personal information has a high risk of influence elections.
To take a more direct example, if you are paying your email provider with data, then you are also selling the information of anyone who send their emails to you. The sender is in an impossible position in that they can't know who the email provider is of a recipient (email forwarding is a thing), so the social cost is on the recipient if they sell the information.