16 is worth it if you can spot a noticeable difference between 8 and 16GB today. It doesn't have to be drastic. Things get more ram hungry over time, and I personally use 16GB. I don't usually saturate it fully. I get close enough though. I'm not using an Apple machine at the moment, but that could easily change again.
If you aren't seeing any difference, then it's a poor value. Typically I wouldn't suggest anything that will require more than a year to become a benefit when it comes to future proofing, because you'll probably end up replacing it at roughly the same time either way.
The base 13" macbook air is $900 through the educational store. $180 is an additional 20% of the new price. Improving resale value by more than 20% of the new retail price is very unlikely. I can't find any example from any merchant that supports the claim, so I'm just going to say it's bad advice.
Keep in mind that Apple is also migrating to ARM an their own architecture. I expect third party support to begin to wane within 2 years of transition. It's not like they become unusable. Companies just stop supporting things in their latest updates. Since Apple supplies bootcamp drivers, that can also become a point of contention.