You can come close to a higher voltage mod with a LR carto/atty @3.7 volts, but not a variable voltage or variable wattage mod.
If you were to have a variable wattage mod, you could find the wattage you really like and the mod would supply your wattage no matter the condition of the atty/carto, or even no matter what resistance atty/carto you place on it. (The resistance of coils vary with things like heat and oxidation.)
A good variable voltage mod allows the voltage, and wattage, to be changed at your whim, atty/carto, flavor of
juice, and/or desire for more or less vapor.
Let's use me and my VV this morning. I have a nice 2.5 Ohm, measured by the PV, atty and drip tip on and started the morning with a vanilla flavor. I know the vanilla flavor will give me a good, full, flavor and a nice throat hit with 5.2 volts (10.8 Watt). Now, later in the morning, I do not want quite as much of a TH and want a coconut flavor. I know that the coconut flavor I have is harsh at 5.2 volts with this atty so I drop it down to 4.8 volts (9.2 Watt) and I have a smooth full flavor coconut. I was able to adjust, or vary, the power to give me the exact vape I wanted at the time I wanted it with nothing but a few presses of a button and dripping a few drops.
Now, more than a few folks will be very happy with a set voltage and resistance giving them a set wattage, and that is great. I need different vapes throughout the day. I used to do this with various attys and cartos and different strength juices. Now I have one strength of
juice, but still have various flavors, and one atty or carto on my one PV that gives me everything I need no matter what I need.
If you are happy with a LR carto/atty @3.7 volts, and I am happy with my variable voltage mod, then they are the same in that they make the owner happy, but they are not the same in function or abilities.