This card is crap and not going to see play in vintage, but I think it is important that they printed it because it shows that WOTC is willing to play around with single cards and deck limits with hard numbers (as opposed to unlimited.)
What this means is that in the future it is fully possible we see cards with a bit more of a jacked power level or abilities that become problematic when comboed with themselves, but with a deck building limit of 3,2 or 1.
Personally I would love to see some cards that are inherently legendary as they have a built in restriction of 1 per deck, as I think a card like Mox opal should have always been. It feels like something they always could have done and just did not, so maybe this shows some willingness.