Hi Vud,
I’m a developer too and made an Arduino foot controller (see https://forum.singularsound.com/t/arduino-midi-footswitch/7197/9.
There’s no technical reason why Arduino is ‘better’, so go ahead and use whatever you prefer - however, in my opinion, the Raspberry PI is overkill; MIDI is simply streaming serial data.
For me, I just wanted to prototype something fast, throw it in a box and put some switches on it. There’s plenty of sample MIDI projects out there for Arduino, so it took no time at all to put together.