*It has a couple of plug sockets and can connect to internet from the region you teleported in from
What do you mean connect to internet? usually that needs to work through a provider, and be hard wired. I think for this scenario its safer to assume you have radio signal access meaning you could have mobile data and calling.
I'm also assuming the teleportation is relative to the earth so If I'm on a plane, I wouldnt' want to teleport into my pocket dimension as I'd teleport out of it away from the plane.
One thing that comes to mind is you're basically an extremely hard to catch drug smuggler. The only time anyone will ever find drugs on you is when you're taking it out or into the dimension. Heck, even in doing sales, you can't be easily caught because you can drop off the drugs somewhere remote, and pick up the cash elsewhere. Even if you get "ripped off" the biggest problem for you is the money lost on buying the product, and travel time.
I think having a specialized emergency kit in the dimension would be very valuable. Maybe some explosives if you ever need to clear out an area though that should be rare. Canned food, and water. First aid kit. Some kind of smoke bomb (running away from a situation). Laptop with internet access (if you ever need to hide out, acts a entertainment and a way to hear what's going on in the world). Cardboard box that you can fit into (not certain whether you should teleport back somewhere because people are looking for you? Teleport back, inside the cardboard box to see if it's safe lol). Several rechargeable batteries since you basically have unlimited free power.
I think one of the more practical uses is using it as a home. You can live almost anywhere and have at least a small home. Get a job in the highest paying area you can access, and live in your home for most of the time and you'll save so much because those high wages usually stem from high cost of living.
I don't think you'd want to transport people because the more people that know about your ability, the more attention you'll get which is very bad. The only way transporting people really works is if they're transported while unconscious so they're not aware they were in another dimension.