* put a cap between power and ground
* get some nice ESD-birkenstocks
* don't listen to anybody telling you how it's done
The start of the art is BS and we need a revolution. There will be so many people who tell you that you can only do it in C and if you don't, you can't be taken seriously. The result is that everybody is keeping to C and nobody invests time in bringing new ideas to the field. The chip vendors stubbornly ship you really, really bad C SDK's and have no interest in doing better, for reason beyond my comprehension.
As you mentioned Rust - there is a Rust working group for embedded targets and they do cool stuff, but it's hard and a lot of work. Also, hardware is basically a huge block of global mutable state, so that is a problem to wrap ones head around.
But eventually we have to get rid of "C is the only serious option" which is an argument made by people who know how to write "safe" C and perpetuated by people who can't, but act like it.
[Before you react - I know this is an "extreme" statement and it's not 100% accurate and there is much more nuance to it - it is exaggerated for comic effect ;)]
Could be a case of unfit business model leading to wrong incentives.
Many chips, like a bluetooth chip, don't draw power continuously, but there are spikes. These spike in current can lead to the voltage dropping to low. A filter cap acts against that.
Sometimes, especially in prototyping circuits, where nobody took care of properly designing a power supply, filter caps are the first cheap shot at fixing weird behavior.
If you wanna know more, google the term, there is way better explanations then mine, form people with way more profound knowledge.
So depending on what frequencies you want to filter out you can change the capacitance C.
People already explained the reasons. I just wanted to add that point.