I'm not YCY, but I can do the math.
The nominal voltage of a battery in a mech mod is 3.7 volts. It starts at 4.2 (BRIEFLY) and drops quickly to 3.7ish for quite awhile before it dies pretty quick to 3.2 and then you KNOW it need to be changed.
Using an Ohms law calculator (YCY can do this in his head), the popular 1.5 ohm @ 4.2 volts start at almost 12 watts (where I like em) but quickly drop at 3.7v to 9 watts (still usable) but then fall to under 7 watts.
The main difference between a 1.5 ohm and a 2.4 ohm atty is the size of the wire. A 2.4 ohm will use a thinner wire which is more resistant (higher resistance) but gives a much faster heat up/cool down cycle and has more surface area. Thats a plus for not cooking your juice and for more vapor and flavor. But unregulated, a 2.4 ohm in a mech mod STARTS at only 7 watts, drops quick to 5.7 watts, then withers eventually to 4.3 watts. Not anywhere close to a vapeable range from top to bottom.
But a VV/VW device lets you set the watts to an optimum 10-15 (depending on your taste), and KEEP it there for the life of the battery PLUS you get the quick heat/cool cycle of a high resistance atomizer with thin wire.
You can play with the numbers
HERE and see what I mean. well, the links not working.
GO here:
Ohm's law | Steam Engine | free vaping calculators
If you really want to glean the benefit of using high ohms on a high powered VV/VW device, you might want to check out what I consider an epic thread by a guy who really knows his stuff on the benefits of today's new high voltage/wattage mods, and you have some patience for learning something about watts/volts/resistance/heat flux and surface area I recommend this thread, it take awhile to digest it all but the guy is brilliant, and you'll really understand the advantages of the new high VV/VW devices
here.
I built a parallel 30ga coil based on his theories in a single coil RDA (Prometey) and I have to admit, it even beats my beloved 1.5 ohm HH 357 in vapor and flavor. And not by a little, by a lot.