Paddle is a merchant of record: legally, it sells your software to the customer, which makes global sales tax, VAT, compliance, refunds and chargebacks Paddle’s problem instead of yours. Subscriptions, checkout, invoicing and dunning come in the same integration.
It suits SaaS founders selling internationally who would otherwise register for tax in dozens of jurisdictions. The cost is a higher per-transaction rate and less checkout control than assembling the pieces yourself on Stripe.