Of course it is a good choice.
2lb. per cubic foot density
2"+ depending on your budget (thick enough that the inside surface is above the dew point on the coldest day of the year)
Open cell (1/2lb. density) foam is crap.
If you thought doing the walls with EPS or XPS was good, why wouldn't you think a monolithic layer of an ever higher performance foam was good?
The walls must be dry to apply the foam.