I had to create a prototype. Fast. I got stuck on really weird bugs. Remade. Got stuck on more strange bugs. Remade and was surprised over the exceptionally steep learning curve of something that should be intuitive. Remade everything. Run into so many design decisions that makes no sense whatsoever, that I had to redo everything. So I did it again... Until I realized that it's impossible to use blueprints in any meaningful way. You have to redo each card...

I can't express how amazingly fiddly and buggy this garbage is. Which begs the question:

If you want to make fast designs, use paint, which is faster and looks at least just as good.
If you want to make good looking designs, use Incscape which will be a lot more precise and look a lot better.
Why on earth would you use this garbage?