Which means those coins have better fungibility and have superior privacy IE they make a better digital cash than dash.
No. They have no "fungibility" because they have no universal visibility.
Cryptonote is a privacy - not anonymity - technology. It's a cyphering system, not a monetary medium. (Unless you regard it as 'bookkeeping money in which case it needs to be backed by a trusted party).
The thing about money is, making it private is not the challenge. That is a technical problem that can be solved by a few boffin heads and academic papers without the co-operation of the general public.
The challenge is value. Monetary value. That is not a technical problem but a sociological one which involves lots of complex interrelated properties, not least usability, unconditional visibility, high fidelity with historical properties of money etc.
In that respect, Dash has its priorities right because what gives the tokens at any particular address their value is the fact that the whole world can see them and verify them - albeit intuitively (which is just as important as mathematically). What gives me privacy protection is that they can’t tell the coins at my address apart from those at any other address. Those two priorities in balance are what will maximise value so they need to be seen as complimentary, not conflicting.
If you myopically focus on infinitesimally small theoretical edge cases to the exclusion of all other priorities then that balance is blown to kingdom come (and the value of your currency with it).