When I saw that website first time, my initial reaction to their "business" was also negative.. it seems they need to work on their public image a bit more.
Basically, they are selling equipment in a
kit for people who want the whole solution in a single package.. but by no means this is the only way to go.
Burried in the website are
links to detailed technical information.Their software supports cameras with LAN interface (I went for
this one), it was only AU$56 complete with optics), but it may also support ZWO (you can ask them).
For example, I will use laptop running Linux, because I have it - so it doesn't make sense (in my case) to buy Raspberry.