It is interesting to have 2 PCs. One can be a backup.
However, the main disadvantage is data sharing.
You must share data, at least your internet connection and eventually files between the PCs. This means install a network.
If you are confortable with PCs and do not mind installing the network then why not.
Another advantage beside backup is CPU. You really have twice the horse power [and probably more buying a new PC].
so you trading software won't fight for the CPU and starve. Same with memory, you get the idea.
I have 2 PCs also and a laptop for final backup.
But in general I only use my main PC with dual screen. With one PC active it is easier to organize your screen. Not all software can jump from one PC to another one [because of configuration files, security etc].
So you may end up with the wrong set of application on each PC. Reorganizing might be a pain.
With a PC dual screen, you just move the windows around the way you want them.
Other disadvantage is keyboard. 2 PCs, that's 2 mice and 2 keyboards. this can be a very bad idea when you want to trade, unless you don't really need to type/move things on one of the computer.
I am not taking side.
Both setups have pros and cons. The obvious [almost true] pro with 2 PCs, you'd be up and running quickly. And your job is not to be a computer genius but trade for profits
vpineomatrix