This is just my personal philosophy. I have the domino and the kreg jig. My neighbor has a biscuit joiner. What I have like is a feeling of minimalism. I am moving away from my Kreg jig and will only use the domino. I am still fairly new to woodworking, and once I can do everything with the domino, I see no need to use the kreg: I will sell it or give it away. I no longer borrow the biscuit joiner.
Thus, I would only keep what I will use and if I had more than one item, I would find a way to do the same task with the domino. But again, this is a personal feeling for minimalism. If I am not going to use a tool, or do not want to use it, why keep it. Put it in the hands of someone who can benefit from it.
My friend Fred taught me that relationships are like fine tool makers, what you pay is but a small part, what matters most is the time, passion, and care that was spent and the joy that you have.