I see it as a way for trump to retaliate against dedollarization.
The number imposed on these countries aren't the important thing, but he's just trying to send a message that any attempt of dedollarization will be met with tariff. In the first place we don't even know how they can get the number of the tariff imposed and how to calculate it.
Retaliation is a misguided move, or to put it bluntly, a foolish action, because it will not stop the process of de-dollarization. The retaliation even acted as a catalyst to accelerate de-dollarization, as the rest of the world understood that they could avoid unilateral sanctions and unwarranted bullying from the United States in the future. The best way is to reduce dependence on the US and the USD, not bow down.
As a smart and visionary leader, if you realize that people are gradually losing faith and moving away from you. You need to find ways to draw people closer to you by overcoming your shortcomings, not by bullying them.
Trump is doing the opposite because he thinks he is the king and everyone needs him but no, the world has changed a lot.