Still has to go through all the usual trials, etc, before it can be grown commercially, and then there'd be questions over GM regulation, market-acceptance, and whether the crop is productive and easy to manage for commercial growers to sort. (Usual productisation questions for a new crop variety to have to jump through.)
Also, concerns about the long term (decades+) results of fixing similar issue by only splicing new genes in.
Nature exploits opportunities. If we're still planting monocultures of cloned plants (plus whatever genes), that's still going to be enticing prey. See: Roundup resistant weeds.
I'm not sure that fungus gains anything evolutionarily meaningful from learning to infect this particular banana.
The only thing you get from this is annoying humans, which doesn't sound a very good evolutionary strategy (second only to being used in Chinese traditional medicine)
