New electric blower owner here, thanks for the additional detail. Mine has 2 batteries too and I don't come close to discharging them in 15 minutes, so a big win. I don't think I've had to use the maximum flow setting yet.
Yeah, with the largest batteries available (12aH, which is perfectly doable with a decent backpack system since the weight isn't on what you're holding) I've used mine up to 40-50 minutes in terms of continuous run at maximum power, which is extremely solid imo. Another nice aspect about electric is that when you're not actively blowing it's using zero energy, whereas once started a gas one is constantly using some fuel even when you're just walking around. Using a blower on a larger area often involves a fair amount of blowing-then-repositioning in order to herd things where you want them to go. So 30-50min of continuous run time can represent 1-2 hours of actual usage, which is also about as much (or more) as I'd ever want to do without stopping for a break anyway. And then of course can in principle just swap to new batteries anyway, though that increases TCO.