The general concept of something like the ghost mode just causes lag on the server. You have to separate the players from one another to ensure that they cannot interact with one another or the world properly, and doing it properly tends to be pretty resource intensive. It may add another new aspect to the game, but that's usually at the cost of having the server lag a lot. In this way, it's pretty similar to the idea of "Deathmatch" on TTT, which caused a lot of serverside lag, despite being used on other servers.

I may look into it and see if I can make it work in such a way that isn't laggy, however I'm not making any promises on those grounds, since the history of ghost mode hasn't been great.

The general concept of something like the ghost mode just causes lag on the server. You have to separate the players from one another to ensure that they cannot interact with one another or the world properly, and doing it properly tends to be pretty resource intensive. It may add another new aspect to the game, but that's usually at the cost of having the server lag a lot. In this way, it's pretty similar to the idea of "Deathmatch" on TTT, which caused a lot of serverside lag, despite being used on other servers. I may look into it and see if I can make it work in such a way that isn't laggy, however I'm not making any promises on those grounds, since the history of ghost mode hasn't been great.