Only if paired with a Level 23 Mana Troop:
I’d say so, but 40 Emblems is a lot to spend on a 2% Crit boost.
That’s why I’m stopping at +18 on my Heroes.
Even though you don’t have other Paladins, I’d suggest stopping at +18 anyway, because you can’t remove just the last 2 Nodes later without resetting the whole Talent Grid, which is a massive waste of Iron and Food.