If your product integrates with existing systems in any way, or even is still just a fairly minimal product, this doesn't really apply. You can have clients wh

If your product integrates with existing systems in any way, or even is still just a fairly minimal product, this doesn't really apply. You can have clients who are willing to pay for example for reports your product generates, but it's useless to them unless your product accepts data from one of their systems. You still need to prioritize requests, but to say they're not real buyers is extreme. If you don't believe they'll really become clients, that's what contracts (and maybe letters of intent) are for.