Yes, but that's my point, you see. Because Arm historically has been used for mobile and small devices, there's been a strong incentive for decades to emphasize power efficiency. Because x86 historically has been used for desktops, there's been a strong incentive to emphasize power. It's only been very recently that Arm attempted to have comparable power, and even more recently that x86 attempted to have comparable power efficiency.

Sure, Arm is currently more efficient, but the general consensus is that there's no inherent reason for why Arm must be more efficient than x86. In other words, the only reason it is more efficient is just because they've been focusing on efficiency for longer.

Both AMD and Intel's current gen x86 cpu's are, from what I can tell, basically spitting distance away from Qualcomm's Arm cpu's in terms of battery life, and rumor has it that both x86 companies should be able to match Arm chips in efficiency by next gen.

So if efficiency is a priority for you, I think it's worthwhile to wait and see what the cpu companies cook up in the next couple of years, especially as both AMD and Intel seem to be heavily focused on maximizing efficiency right now