I can't even remember the last power outage we had that was not self-inflicted (a year ago our old microwave oven permanently tripped the residual current device).

Also, according to the article, it seems to pay itself back in 11-12 years. I'd rather pay the little extra to not have a huge lithium battery in our appartment that cannot be extinguished with a normal fire extinguisher if it decides to ignite itself.