Sorry to be a bit thick, but i have looked and all the answers to this seem to be quite old so things may have moved on.

I want to put all my IOT devices on the IOT network on the router  because i want my important devices separate.

From various sources it appears that i can set the IOT to 2.4ghz to make it easier for all IOT's to connect. I can also have an easier password so i can remember and easily type it in.

However, several posts say the IOT network is not actually separate so would i basically be setting up a backdoor with an easy password to my main network? 

Also it appears i shouldn't use the guest network, which is more secure as it will isolate each device so my Hub wouldn't turn the lights on.

So whats the point apart from making the main network a little cleaner therefore faster?

Or do i make the IOT password as complicated as the main one , therefore keeping tio secure so i end up with 2 networks that do actually talk to each other but the clutter of the IOT ones is just on a different stream so the main one can be more productive?

I hope that makes sense