What lets you claim actual resources is the number, plus the massive economic system that it lives within. The economic system is by far the more interesting and relevant part of that, as evidenced by the fact that most assets are not held in the form of money.

And yes, those others are great examples of this principle. The diploma is just a piece of paper and an entry in the university's records. Set it on fire and I still have all the skills and knowledge. Give me a good solid blow to the head which breaks the skills and knowledge, and you've destroyed what's actually useful and interesting, even though the diploma is completely intact. Likewise, citizenship is only relevant because it convinces other people to let me do things like work, cross borders, and vote (which is a whole other number-that-does-stuff-because-people-happen-to-agree-on-it system).

I'm not confused and I don't think money isn't real. I just understand what it actually is, versus what people agree to do with it. It's a typical example of the map not being the territory. Money exists, but it is not wealth or value. Money in an account is a number. Money as a system is a collective arrangement where money can be exchanged for goods and services, usually.