Some have trouble associating Bitcoins to property because they have no physical properties. They should consider what gives Bitcoins it's value. The products and services that can be bought, sold, or leased is what ultimately determine it's value. We may use the market as a reference, but it does not determine the value. given this we can say that Bitcoins are representations of physical property. Very similar to stocks, bonds, commodities, and even fiat currency.
Value is a straw man. It has nothing to do with whether something is property or not. Also you cannot compare bitcoins to stocks or legal tender, because bitcoins are not enforceable by law (you need to enforce them by mathematics).
You are suffering from confirmation bias. You're searching for all the properties which bitcoin may have in common with property, which has a very general and broad meaning. Based on your arguments I can own all the air around me.
Here's an exercise for you:
Are you reading MY words? (see what I did there). I just gave you access to a few letters. I could also send you the encrypted version if you feel that reading should be enforceable.
I found the statement of Adrian-X quite fitting, which I re-quote here:
So Bitcoins are information on the P2P network, when I get given Bitcoin's I never actually take position or ownership, I just get given a right to decide how to direct that information. The idea as BTC as property is merely a convenient concept for relating my understanding to the meme of ownership.