Ok, if you made a .05 ohm coil, and wanted to fire it at 5 volts, it would be 100 amps of power. To safely use 100 amps of power, you would need a 6 battery mod to fire that sucker. relatively safe. Let's say you use a 4 battery mod running it at the max discharge of most batteries, you run the risk of it accidentally firing in your pocket.....unless you were using temperature control. Failure to vape safely risks the battery venting, which means toxic chemicals released, runaway heat buildup, and ruined mod and battery in the best case scenario.
Builds under .2 ohms should really be done in temperature control. Mods put that lower limit for a reason. What makes temperature control so different that it can fire real low ohms? Well, it fires what it needs within the mods parameters for a safer vape. If you try to push a mod or battery past it's limits, you're asking for trouble.