Shorter version
Watts are watts, and the amount of watts you get from your battery is determined by the amount of current (Amps) drawn times the voltage. The amount of current drawn is impacted by the resistance (Ohms) to the current. So less resistance, e.g. lower Ohms, will let more current flow and give more watts for a specific voltage. If you use a mech mod, your voltage is limited to 4.2V (fully charged battery) to about 3.3V (fully drained battery). So reducing your Ohm resistance is the best way to increase your wattage for bigger clouds and richer flavor, since you can't increase your voltage. That's why people sub Ohm. Of course there are safety issues if you reduce resistance too low and over stress your battery by draining it beyond it current output limit - e.g 20Amp or 35Amps as listed on the battery.
The beauty of regulated devices is that they allow you to adjust your voltage to give you your desired wattage output regardless of your resistance. So you'll get the same 32 watt output with a .5 Ohm build at 4 volts and you will with a 2 Ohm build at 8 volts. Plus regulated devices have software to prevent you from exceeding the current drain limits of your battery.
If you use both mechs and regulated mods, then I can see building subohm for flexibility when switching between regulated and unregulated voltage power sources. But if you use regulated devices exclusively, then don't worry about the Ohms. Just build the best combination of wire thickness and wraps to fit your RDA/RBA design and produce optimal flavor. Some people say that more wire (e.g. more wraps) gives more surface area for the wire to vaporize liquid off your wick and thus gives better flavor. Some also say that thinner wire heats up faster and gives a stronger "hit." More wraps and thinner wire means more resistance (higher Ohms) since the current has a longer and thinner "hose" to travel through. But your regulated mod lets you boost the current (by boosting the voltage) going through the wire to produce your desired wattage.