It will contribute to the centralization of the Fediverse, which is something that’s not good, as competition is required.

One might say that multiple apps will be bad due to them needing to be very complex to suit to everyone.

However, many 3rd-party apps can provide extremely specific experiences, and with enough effort, you can find out what suits you. I’m using Memmy, since it contains the best parts of most of the apps I have used are designed this way. One app does not need to contain everything. In this case, quantity is better than quality.

One might also say that competition will create toxicity as people will pick sides.

I disagree. Nobody ever fought about whether Reddit is Fun or Apollo was better. That’s because they both contain different experiences. It’s like conparing apples and pranges; there’s not point comparing them.

This is why I believe that there should not be an official app for the Fediverse.