Legal tender laws are likely more qualitatively significant than ability to pay taxes in of itself.
I'd be wary of the chartalist/state theory of money, since it's somewhat of a truism (state theory of money is correct for money chartered by the state). It tends to ignore that many local currencies have also emerged through different channels.
MMT as promoted by Mosler, Wray, Kelton and Tcherneva is also a syncretic and often uncredited mix of a variety of economic ideas, generally as a clout for the policy activism that its founders promote.
Size of impact no matter how minuscule, it still poses problems for a chartalist theory of money.
Bill Mitchell's economics frequently take a backseat to his rabid quasi-conspiratorial rantings about the neoliberal order that are in turn instrumental to influencing his economics, unfortunately. James K. Galbraith is far less erudite than his father, who was actually a decent institutional economist, if disagreeable. Abba P. Lerner was a great economist, but his functional finance proposal proved theoretically untenable in light of public choice critiques and has yet to practically materialize anyway. He was also against unions, interestingly enough, in his famous paper "Money as a Creature of the State".
I'd overall rank MMTers are some of the lowest quality of the heterodox, honestly. The circuitists like Marc Lavoie are much better out of the broader Post-Keynesian school.
I'd be wary of the chartalist/state theory of money, since it's somewhat of a truism (state theory of money is correct for money chartered by the state). It tends to ignore that many local currencies have also emerged through different channels.
MMT as promoted by Mosler, Wray, Kelton and Tcherneva is also a syncretic and often uncredited mix of a variety of economic ideas, generally as a clout for the policy activism that its founders promote.