I always see laptops come with larger bricks that have separate mains cable which plugs into the brick. Even if the adapter has some low power rating.
Example for comparison:
On the right is a standard laptop adapter.
Same price, same connector, same protocol, same power rating, far different size.
Why is that so?
Actually, the GaN adapter on the left also advertises itself as being meant for laptops, but by default, almost all laptops will come with something like the one on the right.
Or is it simply cheaper to manufacture while being sold for the same price?
In general with electrical things, the longer it will be operating at a higher usage the bigger the need for heat dissapation and more robust parts. Phones of the same power rating still have less juice, as in smaller batteries, and have less power usage overall.
While the power rating may be the same, the volume of energy is not the same. Like running water through a straw and a hose can have the same pressure but way more water is going through the hose.
Watts are part of the electrical properties along with volts and amps. Laptop chargers have the same watts and volts but more amps.
Edit: I got the calculation wrong, but the point is that more power goes through that laptop brick in a shorter amount of time and it needs to both handle the higher load and dissapate more heat.
The equation to determine watts is P=VA
If you have the same voltage and a higher amperage, then by definition you have a higher wattage.
Watts are part of the electrical properties along with volts and amps. Laptop chargers have the same watts and volts but more amps.
This is incorrect, Watts (power) is the product of amps * volts. The formula is P = IV. Anything with the same power and voltage will have the same amps.
The volume of power consumed would be Watts * time and gets you to capacity and usage units like watt-hours.
