My guess is you had the DAC plugged into the PC first. The method used depends on what device the DAC is plugged into. Generally speaking, ALSA is used by Linux which the Pi runs. ASIO is used by windows. Plug the DAC back into your PC and see if it then shows up as ASIO again.
I would say that you probably won’t hear a difference. But, as most things in audio, try them both and then use which sounds best for you.
There isn’t really any uncertainty. If there was it would become obvious quite quickly because it would break things like MQA. My experience switching from Windows 11 ASIO to Linux with ALSA on the same box was that it was much more reliable. If I power the DAC down, when I restore power it is always there in Roon. That was not always the case in W11. A lot of that is down to driver quality which can be quite variable in Windows.