I'm all for technology, after all it is what I do for a living, but you have to be careful. Due to my job I know all too well that technology can and frequently does fail, and relying entirely on having goals, cautions and send offs just on your watch strikes me as a massive risk. My Apple Watch 6 for no apparent reason rebooted itself yesterday on over 80% battery, what do you do if that happens in a game? There has to be a plan B, even if that is something as basic as jotting cautions in a notebook at breaks in play, or even writing the numbers on your hand.
Best case scenario if it goes wrong is you can ask the clubs or ARs for details of cautions, worst case is they can't remember or even worse you go to caution someone and don't realise they've already had one. Certainly not a risk I would be willing to take.