[bryanrasmussen]

Because businesses, in order to match compliance rules for their business types, size of business etc. often have lots of rules and processes in place about buying things like software, thus it becomes really beneficial for a manager if they can buy all related functionality that is needed by their business (especially functionality that is required by law) in one place.

Furthermore considering that some things will often be very complicated to do because of legal burdens it makes sense that one piece of software for doing invoicing handles all your invoicing needs across all markets you operate in. And suddenly when that happens it might be that you get a more complicated piece of software than if you bought 10 different pieces of software each supporting the standard needed for a particular market.