From experience, (1) isn't really a problem. If payments bounce they do so within a few days due to insufficient funds or fraudulent use. After that, refunds are extremely rare. Esp. since most European countries have easy systems for small claims which allow you to claim the money back.
Regarding points 2) and 3), I wasn't aware of those limitations. I admit to never having tried to use SEPA direct debit with Stripe, I just saw it in their docs.
Regarding 1): is it? Credit card payments can also be charged back, often for a period longer than 8 weeks. And both "aaS" products as well as certain retailers selling and shipping physical goods, do offer direct debit. I can't quote any fraud rates, but it certainly seems possible to do it.
Why does that affect SaaS businesses specifically? I would think that's at least as much a problem (if not worse!) for businesses that do non-recurring sales and also for businesses that sell physical goods or non-scalable services. It sounds like if I pay for a steak or a haircut with SEPA, I can get a full refund eight weeks later and make it the restaurant or barber's problem to chase after me for the money, right?
Actually you can. A few years ago, when paying with a German bank card, very often the transaction was turned into a direct debit transaction, because they used to be cheaper.
This used to be very common in supermarkets. Every time you had to sign the receipt this was happening. It's not as common nowadays as the fees are now more or less the same.
1) SEPA has an 8-week no-questions no-appeal refund model, which is fundamentally incompatible with a SaaS business
2) Stripe doesn't support SEPA on Checkout
3) Stripe doesn't support SEPA on non-EU/US accounts