Yes, in that case they'd have to buy Kindle format books too. But also realize that this is going really slam the waiting list demand with the number of customers wanting to check-out eBooks. Once word gets out, Kindle owners who previously have been sitting on the sidelines are going to come running to Overdrive.
I agree though, budgets are tight. They're going to have to look really carefully across the entire spectrum of what their particular base of patrons want from the library .... genre and format. That's not anything new for library acquisition specialists.