OK...more seriously...we never had any tree fires. We never had any problems. But then, we didn't expect to run the lights when the tree was dried out, and had lost 3/4 of its needles, either.
I've had mixed feelings about the C7 bulbs over the years. I can't say I liked them when I was young, but they were what we used for primary lighting.
I decorated the last family tree 20-some years ago. For a long time, I didn't decorate a tree of my own. During that period, looking ahead, I played with some mini lights, and thought "this is a better solution." They were surprisingly bright in a dark room. Yet ran cooler and probably used quite a bit less power to run.
Then, when I started decorating a tree again, I used mostly mini lights, which do seem to work nicely. But...I still had a small strand most years of C7 bulbs. Not run constantly, but it adds a nice nostalgic touch for "special" moments during the holiday season.