Don’t forget the droid being tortured with a hot iron in Jabba’s palace, in addition to human emotions the droids also can feel some degree of physical pain. R2 has a famous yell when he’s electrocuted, 3P0 is always complaining about his aching joints, his cowardice even to an extent is to avoid pain or destruction, so he also has a sense of mortality. Both even have private feelings about situations they’re in, while they’re always in servitude they can still feel affection for their owner but have a sense of autonomy, refuse commands or act stubborn. “We’ll be sent to the spice mines of Kessel” so even a robot can differentiate enslavement vs completing any other task like a real machine.

I also feel that the droids ability to feel sensations is neccessary for their ability to feel emotions, which is also connected to their ability to understand humans and required for their own sentience and sense of independence or personal identity.