Why do we "classify" crypto by market cap ?  Because we somehow think this is a gross measure of the "value pool" of the thing ; in other words, if new economic entities were to "take over" the entire thing, that's more or less what they would pay for it.  So that's "what it is worth".  It also means that if you possess, say, 1/10 of the system, that you will be able to obtain grossly, 1/10 of the market cap if you sell it over a period of a few weeks or months.  (yes, the market will lower a bit, but if it is sufficiently liquid, it will absorb it).

Well, this is not true with DASH.  If you own 1/10 of the DASH stash, you won't be able to sell it for 1/10 of the market cap.  You will simply crash the market.  Because the integrated demand, even over months, is not that big.