The "or deals damage" was an erratum, not in the original printing. Like any erratum, not everyone will even be aware of its existence, and so certainly not everyone will use that rule. Personally, I think it was a bad rule, because the wizard enabling the fighter to contribute vs. an enemy resistant to nonmagical damage is good team play, but if you accept the existence of the erratum, it's a clear rule.

Although, even with that rule, making and using weapons is still possible; it just disappears after one hit. If you're making an arrow, that probably doesn't even matter at all (though it'd take two players' actions just to get one attack per round that way, occasionally but not usually worth it). But what if you're using regular arrows with a conjured bow? Is it the bow that's dealing the damage, or the arrows?