that criticism ignores that part of the arc of that movie is that Indiana Jones goes from not believing in the Ark's power at all ("I don't believe in a bunch of magic superstitious mumbo-jumbo", he tells Marcus) to believing in it. His character has made a turn. For that, the adventure was worth it.
And in the conclusion, it's not his brawn that saves him, but his new FAITH that saves him.
Which is very clever, I think.