I very much disagree with your claim that invoices don't apply to SaaS apps. Without an invoice being issued, it's a pain for my company to account for handing

I very much disagree with your claim that invoices don't apply to SaaS apps. Without an invoice being issued, it's a pain for my company to account for handing over money to you. In fact, it's enough of a pain that I won't use any SaaS app - or company for that matter! - that doesn't issue invoices. I've also had people contact me, asking to pay on an invoice basis. I generally only do so for annual subscriptions, but doing so has brought in extra money I'd otherwise have missed out on. When you have a system that automatically generates invoices, it's not much of a pain to do so.