I have an IPV3 which is a 165 watt mod after the firmware update. I also have a Hex Ohm and Sigelei 100 watt mod but the sig was loaned to a friend that quit smoking cigarettes.
My daily driver setup is the IPV3 with a Tugboat V2 that runs at about 40 -45 watts throughout my day, I'm using 26 gauge coils at .4 to .6 ohm dual coil builds. But when I'm using different builds in my Darkhorse or Mutation X I sometimes run somewhere around 70 watts.
Even if I vaped at only 40 watts all the time, I would still want my high wattage mods unless they offered the same mod with the same features and chips but with less wattage. Right now I can buy a 50 watt sibling to my high wattage mods, that is missing some features and fixes, and may house one 18650 instead of two, for about $80. Or I can buy the 150 watt version with a lot of updates and improvements that's dual 18650, for about $90 or so.
The variable voltage and variable wattage features allow me to build with lower or higher gauge wire, and adjust the performance to match my build, ao I can get my wicking and coil surface area just right for my personal preferences and adjust my power to match accordingly, and use whatever wire I want. With a mechanical mod, I can get awesome performance if I build the right coil, but I'm limited to building with a resistance low enough to make the most out of the battery's limitations,
I used to wonder the same thing about the wattage race, but since I've become more familiar with regulated box mods and high wattage mods, I've found there's many reasons for buying the higher wattage mods that are on the market now, with headroom and wattage being on part of it.