president is single seat, so it would be Score Voting. And that would be quite practical, and simpler ballots than IRV. If some states refuse to switch to Score ballots, you just count their ballots as Approval with only one choice filled out. Or maybe every candidate fills out a ballot and publishes it, and voting for a candidate means voting with that candidate’s Score preferences.
An advantage of this is you get rid of the need for a party primary. So e.g. Bernie supporters would have been able to vote for him and he might have beat both Hillary and Trump.
Allocation voting supposedly has the same benefit, but the ballot is more complicated.
Overall I don’t see any legitimate argument you can make that IRV is any good at all when it comes to practical matters. The only real points it can make are that it is more expressive than FPTP.