Why use CAT8?

Hi, why would someone want or have to use a CAT8 cable (or CAT6a/7) for things like 40Gb or uplinks in general when fibre cables can do the same thing but don't seem as complicated or difficult to implement? Things like...

Will I need to ground a CAT 7/8 cable when connecting things up?

What type of connector will I need?

Possible heat issues with higher data rate cables?

Etc...

It may be an odd question to ask but it came up when debating between copper/fibre and i agreed that fibre would be the best option certainly for distance but for things like 1Gb or 10Gb links over distances shorter than 90m, there really isn't any difference between copper and fibre in an environment that isn't high in noise as well. But for things like 40Gb uplinks etc...fibre would be a far better choice I said for some of reasons I listed above.

Does anyone else have any input with this?

Thanks everyone