Whoever tells you to "sub ohm" and then recommends doing so on a regulated mod, has no idea what they are talking about. It's just bro-talk. Words that may sound cool but makes no sense or has any foundation in reality.
The coil's resistance determines the power output from a mechanical mod. In a regulated mod, electronics determines power output. As such, whether you "sub ohm" or not - with a regulated mod - makes no difference. In terms of end result, 100 watt from a mechanical mod - with a sub ohm coil - is the exact same as 100 watt from a regulated mod; with or without a sub ohm coil.
I am not saying "get a mechanical mod if you want to go "sub ohm". I am saying you can get the exact same results with a regulated mod - with or without going "sub ohm". Regulated mods don't care about the coil's resistance as long as it's within the operational envelope. E.g. some mods may require you to go below a certain resistance to get to the max power output. Other than that, the resistance of the coil has no - none whatsoever - impact on the end result.