I've seen several sources explain the colloquialism in different ways. One says the っちゃ is a slang way of saying よりの, as in ありよりのあり. Another says it's a slang way of saying と言えば as in ありと言えばあり (which I frankly find more likely).
Since both full sentences point to rather different sentiments (the affirming attitude of 'it more than exists' vs the unwilling 'well it is there') I thought I'd ask if there was anyone familiar with it.
Is it one of the two sentences, or am I misunderstanding the sentiment of one sentence, or is it a shortening of something else entirely?