Android customization is sort of like junk food - enjoyable in the moment, but not meaningfully improving your life.
I very much hate the default Android and iOS experiences. I guess the downside is that making my phone more usable means, well, I actually use it more (i.e., too much).
I use my phone more than any other device and having it be "beautiful" is an important part of my user experience
At this point any decoration in real life is useless because not productive
Hard disagree. I assume you have some technical background, that's why you consider it not meaningful. Go speak to someone that knows nothing about it, which is the majority of the people I assume, I'm pretty sure they learn a lot in the way.
For instance, taking control of my phone's three physical buttons with custom double-press and long-press actions that are contextual is so useful I can't imagine using a phone without it. I've also added a custom contextual action to double-tapping the back of my phone that I use constantly. This uses the phone's accelerometer and, surprisingly, works perfectly with no false positives. I use my phone a lot for reading e-books, controlling home automation, photography and other use cases where I'm switching between portrait and landscape modes frequently. Customizing automatic screen rotation to be per app, by time of day and even by location is another one of those seemingly little things that's just so nice in constant daily usage.
Some people argue all these things should just be built-in to phones and "it's a bug" the designers didn't just set-up everything "correctly" in the first place. But the reality is people have different innate preferences about some kinds of usage modes and defaults. For example, I'm highly spatial vs my wife who's very sequential. She prefers contextually adaptive "smart" interfaces that change to list the most likely options first. She can't imagine why anyone wouldn't want that. However, my brain expects stuff to be in the same place it was last time and it throws me when things keep moving around. I think this is more than just a preference or learned behavior, it's an innate trait like handedness. While people can force themselves to adapt across this divide, it will always be uncomfortable and slower.
Then there there is the current UX design obsession with "simplifying" interfaces by removing features, reducing density and increasing the remaining spacing and typography sizes to the point of, IMHO, insanity. This is another reason when it comes to devices I'll use constantly, I consciously choose those I can significantly customize and adapt (eg Android, Windows, Linux, Firefox, etc). Of course, I don't customize every use case. What matters is having the option to do so for those usages which make a meaningful difference to me.