In my case, ISP charges you extra if you decide to keep the paper bills instead going for "eco bill" pdf file send by an email; same goes if you decide to opt-out from company selling your number elsewhere. Last time while getting new contract, 3 different people at local company's office tried to convince me that I can "win some fantastic rewards" if I decide to let them do with my number and personal information whatever they like.
I did opt-outed but they manage to sell all my numbers present on account elsewhere and somehow every month around time when bills arrive, I'm getting bombarded by robocalls - either about photovoltaics or central heating replacements. They claim they didn't do it but they can't explain why newly added number that has all opt-outs receives calls at the same time with the rest.
I'm old enough to remember when banks and other companies would charge extra for the privilege of paying online.
Probably what happened here was that a mid-level manager had a goal for 2021 to reduce paper billing by X percent. And came up with this as a quick trick to do it. Departments externalise negative effects to other parts of the company all the time. What they care about is their own goals and looking good to higher management. Not the interests of the company as a whole. This will only change when something causes a ruckus and top management finds out about it.
Also, the company is not really losing anything, the customer will sign up again, has to pay reconnection fees and will probably be forced to e-bill "because paper billing is no longer available for new customers". Triple win for the company really.
Of course the customer can move to another company but they'll probably want to keep their number and the whole portability rigmarole is much too difficult for this type of customer.
Then there is the group who are still going to insist on/need paper bills, but use technology enough to catch the email about changing and use the opt out process.
I wouldn't say it's a dastardly plot to kick my elderly neighbour off their service, but simple disregard that people like her that would fall through the cracks while they're trying to save money with the first group.
Old people are exactly the type of people that would carefully study letters that come in the post. Unlike people my age that would bin anything that comes with the bill thinking it's probably just commercial crap.
But of course this is precisely the reason they do it by email. Dark pattern..