I play skyblock quite a lot and i don't think that the /shop command is not beneficial to the player. It is a good idea and easy to be able to access the shop at any time, but i think that making a real shop to be able to go into and buy items would be better. This means that there is more variety for the player to be able to buy and sell items. I have built an example shop at plot ID:-98;-84. I will also include screenshots bellow.