There are a couple interesting differences between the US terms and the CA terms:
1) The CA terms say "you [...] will not use the Service to accept payments ..." while the US terms has the more-broad limitation "you [...] will not accept payments ...". I wonder if Stripe in the US actually cares about payments you accept using other services (seems unlikely).
2) Only the US terms ban "personal computer technical support" or "predatory products or services".
3) The CA terms have a broad ban on "any product, service or activity prohibited by one or more Card Networks".
I don't think that bans anything Twilio-based. I'd get in touch with their (usually very responsive customer service) before engaging, but it looks more like they're trying to prevent people from engaging in activities that could allow for anonymous calling.
Which kind if makes sense, if they're looking to never have to be involved in a lawsuit where someone uses said prepaid phone card or anonymous calling service to utter threats, plan terrorist attacks, or other random illegal stuff.
I'm a bit disappointed I can't use Stripe for my online, bespoke shotgun smithing company.
More seriously, from the way that's written (quite non-legally) it's clear they don't want undesirable business. If you're on the edge, I'm betting a simple call/email would clear things up.
(44) telecommunications equipment and telephone sales,
(45) timeshares,
(46) travel agencies or travel clubs,
(47) online or other non-face-to-face tobacco or e-cigarette sales,
(44) weapons and munitions
That's a risk category issue. Porn is categorized as 'high risk' and you need a different merchant account class and associated review procedure for that. You will also pay (sometimes much) higher fees, potentially you'll have to accept a hold-back period and there will be a periodical high-risk fee that you need to pay.
Is processing payments for porn sites so much different that companies that specialize in it exclusively are needed? Why can't a company like Paypal or Stripe support those merchant account classes and procedures?
It's all about the rate of chargebacks and fraud. I would hardly be surprised if your average porn site was subject to both frequent chargebacks and heavy use of stolen credit card numbers, if not both at the same time.
That and association. PayPal just doesn't want their name associated with stuff like that. It's hardly limited to just porn. Anything remotely sexual is rarely sold via PayPal or a major non-Adult-oriented payment processor.
There are some legitimate business apps that not allowed. e.g. anything twilio based: (36) prepaid phone cards, phone services or cell phones