Maybe take few minutes to ask some question from own point of use.
What is the major reason for having a box mod?
a) Batterylife, normally the one which drives into box mods
b) Wattage, do i really need that much wattage
c) I've been reading so much about box mod that i must have one
d) Dripping, once you get into chasing clouds, no turning back, gotta have box mod for high power
Beside tubes, box mods has some advantages, you can charge them using USB almost everywhere.
So, carrying around box mod, even longer trips, batterylife is a lifesaver.
Then you do comparison of box mods size, carrying around huge box is not an easy task.
Smaller box mods has also usually shorter batterylife, but easier to carry.