There is certainly a cost in collecting payment. Going to the bank, dealing with returned checks, chasing down checks, mailing invoices. In the end, in some cases, it might actually be a little cheaper just to take the card.
As we grow in size, and we hire people to do things that I used to do "When I had a second" you start to realize there is a real cost in the administrative tasks a business needs to perform.
Purchasing, for example. I used to handle most of it, but with all the supply chain issues, vendor errors (I'm looking at you Canon and Midwest Sign/Grimco) and just the huge amount of inventory we need to keep on our floor, it has become nearly a full time job for us. It's not a cost you really account for, until your business has to really start paying someone to do just that.
Because we pretty much only accept credit cards, accounts receivable is mostly just a function of bookkeeping, and not something we need a specialist for.