It can be quality code written by good engineers, but there are issues you won't see until you deal with big numbers. The problem here is that Swift seemed to b

It can be quality code written by good engineers, but there are issues you won't see until you deal with big numbers. The problem here is that Swift seemed to be a cool language that it might work for a "Hello world" app. You won't notice any problem until the thing grows up to a certain point. For example, I work in embedded and I am proposed with a new "X brand" Chinese Modem to integrate in our devices. I don't recommend it but since it costs less I'm pushed to evaluate it. I am handed 3 samples and they all work fine, so management convinced themselves that Brand X from China is the way to go. Once in production the modems started to fail at a 10% rate (10 devices over 100 won't work). And that is a problem you only see only when manufacturing a certain quantity of devices. Now there are delays, an ongoing battle with the manufacturer of modems and a unhappy customer (that's why I didn't recommended it).