As long as you can replace the battery in your weedwacker when it goes. It's still not as logical as a machine that lasts forever with maintenance. it depends on the size of the power tool, but often they're the last place you want batteries because batteries are heavy. Motors can be too, but fuel is much more energy-dense.

Incidentally, I think people ignore plug-in tools too much. I have an electric blower and an electric pressure washer that run off mains power, and they are both light and strong. It depends on how far you have to go. For shitty blowing leaves off my deck it works great. The pressure washer is generally close to the house. This is less good if you have a lot of property, but I do see many situations where peopel would be better served not carrying a battery around.