Add struts to the HWA, and you've created four more interference drag possibilities. I seemed to have misplaced. These comparative arguments assume identical wings and fuselages with only attach point changes. Clearly, or maybe not so, we're in the theoretical here. So, attempting to compare boundary layer effects between a Cessna 150 and Piper 140 at the airport next weekend, assuming it could be done, is really an apples and not-apples situation.
Tradeoffs are abundant.
Perhaps the struts enable a weight saving in the wing structure of the HWA which is more beneficial than the drag penalty. LWA might have shorter main landing gear, because they can protrude straight down from the wing. The relative position of the wing and horizontal tail is significant. Do you want a stall warning that consists of natural airframe buffet caused by disturbed air from the wing impinging on the tail. Perhaps you are content to rely on that little tab in the wing's leading edge and the light or horn it's supposed to trigger.