VW is sometimes said to be "set and forget", and up to a point, there's some truth to that.
Assuming you're using the same liquid, you'll (theoretically) get the same vape no matter what the resistance value of the coil. So if you replace the coil and the new one happens to be a different ohm value, the battery in VW mode will automatically adjust the voltage to deliver the same heat to the new coil. Or if the coil value changes over time, again the VW mode will automatically take care of that.
Now, if you change to a different liquid, you still might want to change the watt setting to get the best flavor from the different liquid, so it's not really "set and forget."
In VV mode, you tell the battery what voltage to use. The battery will then deliver that (within it's capability, of course) no matter what the coil resistance, so the vape power will vary depending on that resistance. Change coils, you have to change the voltage to get the vape you like. You can do the math, if you want, to calculate the watts, or, like most of us, just take the voltage up in steps until it starts to burn, then back off a step or two.
So in a sense, VW mode is "easier" - once you determine the watts you like for a given flavor, just set that. And maybe change it to the watts you like for a different flavor...