Some storage beds come with an internal middle divider that helps to boost the structure and prevents the upper board from collapsing - while this is useful, it also greatly constricts how much stuff you can put in the storage section.
In you can, try to choose a bed without the middle divider (and a much stronger/thicker bed base) - We realised that this can sometimes cost more, but it's a worthy investment!
The biggest benefits of our storage section is the ability to store thick/large items like luggage which would otherwise have to take up precious space in our household shelter.
We specifically chose a model that had a deep enough section to fit most check-in baggages (the showroow we visited even had a 'fake' luggage there for us to test it).
The depth of our storage section is about 30-31cm!
Deep storage is a must - but don't forget to add on the height of your mattress! This was something we didn't account for sadly - we were very focused on getting spacious storage and a thicker mattress (for neck support! back support! Lumbar and spinal health!!!) that we forgot to account for the total height of our bed.
As a result, our bed currently stands at a grand... 70cm - which means Duck's short legs don't touch the floor when she sits on it, and getting on the bed always requires some fun thigh stretches :")
Unless you're the Hulk, it's quite unlikely that you'll be shifting your bed once you move in and settle down - especially if you've got a king-sized bed like us!
We were quite intrigued by the fact that our bed's storage section has a removable base - we always assumed that we would remove it to clean the floor - but we have turned out to be lazy people who can't be bothered LOL.
Still. a useful thing to consider if you're buying your bed - do you need the base to be removable?