Backcountrypilot,
Greetings and welcome to the iFly forum! It is great you are helping out a young pilot earn their PPL! Way to go! I think iFly is a very good tool to use to help teach flight planning, after they have done it by hand on a real chart...just in case!
Your question is a good one and has been asked a few times, with various comments over the years.
The WAC Chart, or World Aeronautical Charts aka, "Wide Area Chart," is just that - a broad overview chart to plan longer-than-usual cross country flights. I was sad to see them go, as I always kept them in my plane for planning. They are especially good when getting around large bands of weather on a long cross country.
iFly knows the charts they are showing are indeed technically "obsolete" but many of us (including me) strongly believe they serve a good purpose in long-cross-country planning. The last update to these was at or around 2015, when the FAA decided to cease updating them.
For example, I just planned a X-C to Florida from Pennsylvania...I put in my airport and the destination on the WAC to see what it looks like, and try to AVOID the major areas of open ocean, large mountain ranges, and Class B (large airports like Atlanta, etc.) with rest stops every 225 miles. The WAC is perfect for this type planning. Or, for those going to OSH from the east, who do not want to fly over the Great Lakes, etc. The WAC gives us a broader perspective of the features - that is really all.
I then go into the updated and current SECTIONALS (by simply drilling down) to do detailed leg planning, and avoid SUA's MOA's, R-AREAS, P-AREAS, etc. Sounds like you did that as well, which is the right thing to do. Now that you know this, you can skip using the WAC and go right to the SECTIONALS for planning if that is your personal preference.
BTW, there is actually a chart that is of LARGER scale than the WAC, and that is the GNC-A (for all of the CONUS) or even bigger, the GNC charts...usually so broad they are of little value to us (mostly for transcontinental flying or oceanic flying).
Hopefully, iFly has no plans to discontinue the WAC perspectives for wide-area-planning as many of us value them.
Again, thanks for checking in and asking this good question. Hope your nephew gets his PPL soon!
Regards, Mike N714AJ