Tables?

Can someone explain me what exactly is these tables?

Is it a storage engine? If so then why is it good. (it must be good since vex made it)

Its a replacement for handle vars, instead of getting I2S(H2I(h)) every time u use Get/SetHandle it just gives u it in GetAttachedTable, which you can then use with the other functions.

Zhis is much more. It even returns a number if you request one and store everything to that number, and the number itself is attached as shadow told you to triggers timers or whatever type of handle. So you could store multiple things to one missionkey without having big issues. (By the way: Every number you use will not appear again as a returnde number of the depending func, exept you clear it)
I think the system is very good, even if I actually don't use it.