Welcome to radical constructivism :) The question whether other people or cats can experience emotions is in fact a problem people have been thinking about quite a lot. Answers are not very satisfactory, but one way to think about it (e.g., some constructivists would do that) is that assuming they do have a conscience simplifies your world model. In the case of “AI” though, we have good alternative explanations for their behavior and don’t need to assume they can experience anything.
The other important bit is that not assuming some phenomenon exists (e.g., “AI” can experience emotions) unless proven otherwise is the basis of modern (positivistic) science.
Yes, in the sense that “thing moves around and does stuff” becomes more predictable if you assume a certain degree of consciousness. This is easier than “thing is at this position now, was at a different position before, was at yet another position before that”. You reduce some of the complexity and unpredictability by introducing an explanation for these changes of world state. In my world, so far I worked well with the assumption that other humans and animals have some consciousness and at least I’m not aware of any striking evidence that would raise doubt on that.
Yes, that’s a problem, but it’s relatively similar to the other one. It’s actually quite hard to “prove” anything with real world connection. However, in the case of other humans/animal consciousness, evidence suggests so (at least for me). The evidence in the case of “AI” is different, though. For example, they seem to have no awareness of time and no awareness of the world beyond the limited context of a conversation. Besides a fancy marketing term that suggests there is something similar to living beings involved, what we currently see are admittedly impressive programs that run on statistics, but I don’t need to assume any “consciousness” to explain what they do.