4. Proximity to the Parks
BoardWalk Inn is arguably best known for its easy access to Hollywood Studios and Epcot. It takes about 20 minutes to walk to the former, and only 5–10 minutes for the latter.
Reaching Epcot this way is particularly cool, because you'll enter the World Showcase at the back of the park via the International Gateway, located between the France and United Kingdom pavilions. From there, you could make your way to Magic Kingdom—albeit in a roundabout way—by taking the monorail to the Transportation and Ticket Center and switching lines. (Only do this if you have Park Hopper tickets though.)
Now, we know you'll be doing a lot of walking in the parks as it is, so if you'd rather not add to that step-count right off the bat, consider taking a boat from the resort to either park.