Laughing gas is nitrous oxide, N2O. It comes to you in one of two shapes, and picking between them is about how you work, not about the gas.
A cream charger is a sealed unit at 666 g, 2 kg or 4.33 kg. It goes on equipment that fits it, gets used up, gets replaced. Nothing hard about storing one or keeping a spare.
A tank at 5 kg or 10 kg is a cylinder instead. A lot more inside, needs a regulator that fits, and needs a proper spot to stand. What you get is not having to stop and change something mid-service.
It is a volume question. A pastry bench working to order does not need a tank. A hotel kitchen making foams across three services almost certainly does. In between, ask how often changing a unit gets in your way.
The rules are the same for both. Supplied for lawful culinary and food-service use, with kit the current manufacturer instructions call compatible, inside the regulations that apply. Look it over before use, never run something damaged or connected wrong, and do what the manufacturer says about handling, ventilation, storage and disposal.
Not sure which one? Tell us the regulator or siphon you have and we will check it against the listing first.