One thing about using suitcases for storage – if and when you move your things are already packed!
The versatility is a great feature and they are an attractive way of storing everything from clothes to office supplies, art items, gardening tools, fabric, yarn, 'junque', seasonal stuff etc. All in the same room! It helps to label what is in what.
They can also be used as tables.
Ease of access is worthwhile to consider; the stacked arrangement can allow for this.
And often they come with a 'story' – either from the person who was selling or the travel labels or addresses written inside.