I'd say the dangers are much less than a heating lamp when combining hay/straw bedding and intense heat. Any electrical devise is a fire hazard, so I'm thinking she was just comparing the two extremes and summing it up but used a poor choice of words.
I think it's a great option for newbies who don't know about heat lamps and how to use them for the well being of chicks...at least the chicks can escape a too hot heating pad but they cannot escape a heat lamp glaring down into a small brooder made out of a plastic tote, superheating the very air they breath and never a moment's rest from it. I also think, as with any type of electrical devise that will be near water that could be spilled on it, that this will also have a danger all its own as different types of pads will be used,unsafe practices will be used, etc.
For me, it's a more natural warmth for the chicks and I like the idea. I don't have many fears of things in my life.....life is hard enough without living in constant fear and worry of every little thing and it can hinder the fun and excitement of living to try to control everything by worrying...which doesn't control anything but has the illusion of doing something about it. Worrying is like sitting in a rocking chair...a lot of back and forth effort, but no one's getting anywhere.
Maybe concerned and cautious but not worried.