Absolutely need cargo storage / warehouse / bays or whatever you want to call it.
Example: Mining... you want to mine, go to station, drop off your acquired cargo in storage, return to belt and keep mining, return and store the acquired cargo.
Why store the cargo? Because you want to either:
a) Wait for missions to pop up that demand these items
b) You want a bigger transport ship and grab all the cargo and transport it to a market where you get a good price on it.
Likewise I really want a storage for modules as well. My Viper is combat fitted and light weight with a 2E (smallest possible) FSD since I use it for inter-system fighting like combat zones and resource extraction sites. However, being able to store a 3A FSD that I could refit if/when needed if I am moving out of the system (e.g. to go do undermining) would be really handy. I know Viper might be a poor example as Class 3 FSD's are widely available, but it becomes a bigger issues with bigger ships.
Multirole ships like Python may end up having to do multiple jumps to find and buy the modules needed to have it kitted for a certain role, e.g. trading. Then when you want to change the loadout later to do combat for example you have to hop around again to find the modules and buy them (but then sell the old ones). Why not enable us to store the modules in our "home system", wherever we define that to be, and thus enable us to change our configuration without having to run errands everytime we want a different configuration.
Certainly the local storage could (should?) come at a price, so you either rent storage based on duration or amount of storage... e.g. X credits per day for Y storage. It could also be scaled depending on the size of the station (Large station or surface base vs Outpost for example), so stations in the center of the bubble or in close proximity to Sol, Achenar or powerplay faction HQs would have higher prices than outposts at the frontier of the bubble.
At the end of the day all I want is to avoid completely unnecessary trips, such as being forced to sell whatever you mined before you can do anything else due to cargo being moved over (yay for FdL full of Osmium or whatever, right?) or having to do endless hops around the systems just to change the simplest modules in your ships configuration.