It was slow and ugly by today's standards but you could still do actual e-commerce well before the web was ready, like buy a train ticket without having to talk to a human.
These kind of useful services were almost all provided by state owned entities (train tickets fit the bill). Other that train, you could also apply for national exams and get the results.
That's also why you ended up keeping a box in your home that only help in very specific occasions (except if you're taking the train two times a week), and most people would just go to the local post office to use the freely available Minitel when really needed.
I think the worst part was that many of these services were late to embrace internet partly because of the Minitel being a stopgap.
I've always heard that e-commerce was enabled by encryption (otherwise no one would type in their credit card / bank details over cleartext) -- what method did minitel use to take payment? Maybe you had an account with the vendor and they billed you out-of-band or something?
That was kinda the beauty of the minitel. You did not have to provide anything. The traffic coming from your telephone line was charged to your telephone bill.
That created some household drama... Who spent 200 francs on porn last month ?
I was carefully limiting my usage to free services, or paid services where I could cut (literally) the connection before the 1 or 2 free minutes. Memories...
My brother managed to spend 2000 Fr in a month, connecting at night. As you said big "household drama" when parents discovered the bill...
But, I think he got his first date with Minitel help :D
I've always heard that e-commerce was enabled by encryption (otherwise no one would type in their credit card / bank details over cleartext)
That's because the Internet is an open network where packets pass through multiple ISPs, you don't know what path packets will take, and sniffing packets is easy. Minitel was presumably a mostly closed system managed by a single telco who could keep out bad actors.
Minitel was a direct modem connection to the service, you also had a payment method on file with them. You weren't sending your credit card info in plaintext across the Internet. Being a direct modem connection, even if you had to provide card details, it would be no less secure than dictating them over the phone to an agent.
