I believe donor100+ should have this command. Sometimes when you are smelting sand into glass it takes a long time and some people loose their patience and you need the glass as soon as possible. I believe donor100's should have /smelt where specific items can be smelted. Lets say you want glass and you have lots of sand, you can hold the item in your hand and do /smelt and converts the sand into glass. You can also do /smelt <amount 1-64> so if you are holding 15 sand and only want to smelt 4 you can do /smelt 4 and it will convert it. I understand that this can be a little buggy if it turns out glitchy, but it really speeds up the community. Of course TannerLittle can add something where you make it so you can only smelt specific items like wood, sand, cobblestone, etc. I hope this suggestion can make it's way through skyblock since it will definitely speed up the community.
We already have /fly, /god, and /enchant. Those ruin the survival aspect much more than a /smelt command would. Anyway, sounds like a great idea.
Neutral. Just adds to the list of what donors can who what greenies can't do. Potentially Pay to Win? Also, #GreenieLivesMatter