I like a simpler and more transparent relationship.
Once upon a time I bought something online for about $10 from what was a legitimate business with an address in San Francisco. About 14 months later they claimed I subscribed to some service and started making huge charges to my card ($150/week). Getting them to stop and getting my money back was an enormously stressful and difficult process.
That's why I have a knee-jerk reaction - not a cold, logical reaction - to online purchases from companies I haven't used before, and I'm not the only person like that.
I've had no negative fallout from purchasing a subscription, and they have very good privacy controls for those who don't want the social aspect (so you can basically turn off other user interactions in many ways). It's there when I need it, doesn't seem to spam me and I probably paid with Paypal (I use Paypal as a way to not give 3rd parties my CC info, a proxy if you will) like most things.
It may look old school and appear at a glance like it's not maintained, but it's updated and run actively, there are a bajillion people using LibraryThing. Logging in to look at my account, there's a link on the right for the latest news posted today about "The January ER Batch is up! We've got 2,960 copies of 89 titles this month." (early reviewer books) https://www.librarything.com/er/list
I've had incorrect subscription charges on one of my cards, and while it was minorly annoying (a search on the card website, fill out a form, repeat one more time the second month it happened) I can't imagine a scenario where it would be "enormously stressful and difficult".
Your card issuer is required to respond when you report fraudulent charges, and if they don't you need a new bank.