The images are all very non-standard sizes, and don't resize automatically.
So to get an image to look right, you need to create it exactly the right size for the template you want to use.
The rest is long winded but straight forward. The interface is typically Amazon, and has no short cuts at all.
For example, you have to add the asin to a A+ template manually. Instead of just being presented a list of your books with check boxes next to them.
The other thing is every store is different. And while you can create one for the US, and use it as the template for UK and Can, you can't for AUS, which has to have it's own created from scratch.
The other languages are in those languages, so you can just duplicate the US template everywhere.
Result for me is my AUS A+ has one less asin than it should have, and I have no idea which book is missing. And with my number of books, figuring it out will take too much time.
I find the whole interface very clunky to use, hence going for a single image with a title and text after it.
But that image is the read order I recommend that crosses 8 series.
And as said, it needs maintaining every time I add a book.
Does it make much difference? Hard to know. No big spike when I first added them. But I've noticed an improvement overall since then, but can't say for sure that's the reason.