It’s common for hardware vendors to provide a working system for demonstration purposes so you can evaluate the hardware without having to learn an immutable OS toolkit. Then when you pick hardware you also do the bring up work to get the kernel compiling from source and integrated with your userspace of choice. At that point you’ll switch to an immutable system.
Hardware vendors in this space can’t be trusted, so you need to make sure the board is actually fit for purpose. Outside of the hobbyist space you have to be really careful. There are often business objectives that rely on the board working a certain way.
This is nice in theory but the amount of vendor-specific libraries can be quite large (e.g. Nvidia's CUDA, libcudnn etc.), which you then have to get working on your new OS.
Hardware vendors in this space can’t be trusted, so you need to make sure the board is actually fit for purpose. Outside of the hobbyist space you have to be really careful. There are often business objectives that rely on the board working a certain way.