Critics have already detonated the movement. While there is an environmental argument for sending fewer chargers, it also helps Xiaomi save money. It can maintain or increase your profit margins, especially for customers who buy an official charger. This can include people who already have chargers – you can’t really take advantage of fast charging unless you have a compatible adapter.
Exclusion does not matter much in North America and elsewhere where Xiaomi has a limited audience. However, you can easily prepare the ground for what is to come. Between that and Samsung allegedly skipping the charger with the Galaxy S21, there is a real chance that you will have to go out of your way to find a device (at least, a high-end device) with a power brick included in 2021.