Yep, it would definitely be difficult to justify running it in production. Accuracy would need to be higher as you said or it would need to be applicable to more tasks such that you can take other models out of production.

This kind of model could be used as the teacher in a distillation setup too though. Then faster training of the teacher is actually a huge benefit since it speeds up model development iteration cycles.

But even if it weren't practical to use in production in any sense, I'd argue there's value in doing the basic research of exploring design space of architectures in this way. This came out of a research team at Google. It may inspire and inform smaller, more practical architectures.