50w will give you tons of battery life (about double what the 20 and 30 have). So, if nothing else, it's worth buying it just for that. Just because you have 50w doesn't mean you have to subohm or use the 50 watts. If one day you want to buy a subohm atty, well you will be ready. If not, no harm, no foul. You can vape at 8w all you like.