Everyone can take their pick; TOU tariffs are not mandatory, and never will be, because there will always be people for whom they're totally unsuitable. Even those who don't choose one will benefit from lower prices as the country moves away from burning (expensive) gas for electricity generation.
Of course smart meters are 2-way meters, and always have been, that's how they receive things like price changes and the like. If you fall into chronic arrears, yes, they can remotely change you to prepayment mode. Quicker, and cheaper for everyone, than the current system, but with the same protections. Probably more, since OFGEM came down on suppliers like a ton of bricks last year.
Yes, they say they can only install smart meters because, frankly, it's their equipment and they can lawfully install what they like. It's always been that way. It's a bit like digital television. They decided to modernise the infrastructure, and that was that. If you wanted to stick with analogue television, tough!
No one will pay for the installation of a smart meter, now or in the future. That's included in your bill. However, suppliers can charge customers who insist upon a traditional meter.
Meter fires are vanishingly rare, for any type. Meter errors are also extremely rare, for any type. Panorama illustrated the administrative and technological flaws in the meter roll-out. The concept itself is fine and, again, will rescue us from our disastrous "dash for gas" approach and the massive energy poverty that has resulted.
Continuing to derive most of our electicity-generation from burning gas is most assuredly not for our benefit. I said that from the start.