I still don't understand the appeal or the point of jamming anthocyanins into a tomato that has a lovely spectrum of carotenoid pigments already.
The 'superfood' tag is a gimmick. Taste will always trump high concentrations of nutrients. We've already sampled some of those - high carotenoid carrots were gross to inedible (as rated by various tasters.) And therefore pointless, since good tasting carrots had plenty enough carotene already. Unless the point was to reduce your food needs to one bite of carrot which makes you gag. May as well go for a pill at that point.

I do like rainbow carrots but tbh the antho I've tasted were not my fave. IDK if carotene/antho flavors don't make the best combo for my personal taste. The white and yellow carrots are delicious. Meanwhile, I certainly appreciate anthos in flowers and fruit and beans and greens and grains. So maybe it is a carotenoid conflict.
As regards the GMO issue, it means a patent and therefore ownership issues for the seed and any crossings that picked up the specially inserted gene. Certainly the opposite of Open Source. Not interested in that material, personally. I am ethically opposed to patents on DNA. And I don't see why the organic movement should accept it. Certainly many organic farmers are attuned to seed sovereignty issues and to growing at least some of their own seed. Since the novelty fruit has a good chance of contaminating their OP's with patented genes, you really wouldn't want it around.
And you're right about the gardeners - many will grow it for the novelty, but what will happen to our seed swaps?
You would not even know if your received seed was crossed until a fruit ripened purple. By that time bees have been all over the bunch, and your season's seed is possibly contaminated.