Little help with tripods and skill tree please

I Saved my skill tree of my armor on the inventory, and now that I’m trying to send it to my new gear it says ‘’ after that, the gear cannot be used as material gear’’ this material gear, is he saying I wont be able to use it to transfer my gear +10, to another new gear I will get when I do the abyss on 1370? or is he meaning another thing? i couldn’t understand, and i appreciate the help!

I´m also curious about this one

i did a test, got a gear to +1, then tried to tranfer the +1 to a new gear and worked, but still not sure what do they mean by ‘’ this gear cannot be used as material gear’’

should mean material for skill tree transfers only i believe