It’s not quite the same as one larger space to the hamster and they may not use the add on bin much for that reason. It also means they have to use the tube whether they want to or not, if wheel is in one and food in the other. So they don’t quite get the ability to have the one habitat if that makes sense. If you put the wheel, food, water and house all in one bin then they probably wouldn’t bother to use the other one as those are the things they like to have in their environment. Tubes can be an escape route as well.
Some people also find the space it takes for two dude by side cages is quite difficult to manage and actually easier to have one bigger cage that takes up less space!
If you prefer a bin to a barred cage I would get the really useful box 143 litre
If it’s more about cost I would get the Alaska cage- better for the hamster - costs about £32.