In theory, I don't necessarily mind an official publisher picking up a manga, obviously.
But in practice I do have a few issues with most publishers.
1. They're late to the party and they capitalize on the work of numerous scanlation groups. Cheap move.
2. Their sites are very often subpar. Not a problem if Mangadex continues to publish the scanlations, but it becomes a huge issue when they become the only source.
3. I have to navigate to multiple other sites to read, with different settings, and rendering. The reading experience is not uniform. And as mentioned in point 2, very often way inferior to the MangaDex UI.
4. Scanlation groups can drop a series at any point, but there is no guarantee that an official publisher will keep publishing it either. So this is not even a reliable positive point.
In conclusion, we gain nothing and we potentially lose a lot. The very few publishers that do a good job picking up and regularly publishing quality updates are rare.