Of the 2 Asus boards listed above, I think the main difference is the Strix is targeted more for "gaming" use, so it can support higher speed memory when compared the Pro, and the audio used is "higher end", plus a few extra features Asus may include.
If I recall, Asus targets the Pro series more as a, entry-level mainstream board for all users if you will. So it's not really focused solely towards gamers, but more so for anyone that needs a PC that require the features that the X470 chipset offers over the B450 for their day-to-day use.