While I don’t believe you need minerals in your water, if you are getting enough through your diet, it is an easy way to supplement your essential electrolytes. Since most of us are used to the taste of some minerals in the water, plain RO water can seem flat.
I started out putting a dropperful of the Aussie traces in my flask and kept adding small amounts until I no longer cared for the taste. I cut back a tad and that is what I routinely add.
Someone on this forum mentioned in a different thread that it is dangerous to drink RO water and that it dehydrates you. From further research, I don’t believe that is true, but perhaps adding electrolytes back in is good for peace of mind. Can’t hurt, at any rate.