My current house is a single story built over a crawlspace and all the HVAC registers are in the floor. In all of the larger rooms, at least one (and usually more) register was placed near an exterior wall and almost always near a window. Looking throughout the house, it seems intentional. I've noticed this before in other houses, and I've talked a few friends and the informal poll tells me that for houses with floor registers built in different states built decades apart, it appears the registers were intentionally placed near exterior windows. In my case, given the layout of the crawl space, it seems like it would have been easy to place them them in other locations.
My amateur intuition tells me that for both heating and cooling, having registers near a window is going to lead to a lot of waste. Is this layout actually common? If so, why?