IMO masturbation is about me. Partnered sex is about us (my partner and I). If I want nothing but an orgasm, I can give myself as many as I want or need, whenever I want or need. If I want a full bodied emotionally intimate experience, I want to have sex with my partner.
But masturbation is one of the greatest forms of self care, being able to give myself as much sexual pleasure as I want is SO good for me!! I don't know how I would live without it.