I agree with PP, I’d be worried about what happens if one machine breaks, I’d have to replace the whole thing. It’s easy enough to stack two separate machines with a stacking kit (with a shelf ideally). I can see the tower has a couple of clever features that make the two machines work together but these don’t seem valuable enough to be worth the added risk of having the machines built together.
A couple of other thoughts,
First, I couldn’t see the washing capacity but suspect it’s small as they talk about how compact the machine is. I have an 11kg LG and it’s a godsend having such a big capacity, reduces my loads per week right down.
Second, I think it’s a condenser only dryer, so you’d have to keep emptying the condenser unit into a sink, there’s no option to plumb it in so the water drains away. I used to have a condenser dryer, I then got it plumbed in and would never go back!
So another benefit of two separate machines is you get to choose the ones with the features that matter to you.