Such is the world we live in. It's smart to reflect on the potential "exit" or liquidity strategies of startups that will be key players in your ecosystem and ensure that you have at least considered the downside risk in the event that that type of exit occurs.
Con: Those Unique Customisations Often Become Available for Everyone
In a world where efficiency is a competitive advantage, having all of your added features and customisations put into a startup's product or service may have the unintentional consequence of allowing your competitors to make use of the same feature. Of course, this risk depends upon your competitors also having some of the same problems you do, and likewise seeking the same solutions you do. In particular, if you now rely upon startup's offering, competitors may well be able to take advantage of the same efficiencies you've just created.