Yeah you demonstrate the loop once and show that other whatever the output of the loop is (damage, mana, creature tokens, mill for your opponents) your board is in the same initial state so it can be repeated an arbitrary number of times (or it's forced to repeat in which case you're in a forced infinite loop).
Paper magic works with infinite combos on the basis that if you can prove them, you can "fast forward".
And someone with a draw infinite combo would definitely be welcome in some player circles (see the Jhonny definition).