There are many long term companies that do these installations. Leaking is not a problem. It is more a decorating and enjoying a more natural light issue than any economic one. Having a solar tube in a guest bathroom saves you the need to turn on a light switch a couple times a day, or less often if you don't use the guest bathroom. That might mean a dollar or two a year in savings at a cost of a few hundred for the installation.
If you have a wireless thermometer like this one
https://www.google.com/search?rls=co...32949956662388
you can see what the temperature is up in the attic for a few days. My attic with two fans never gets over 125. Roof is light orangish and no added insulation. I did not do a pre-installation check so I can't tell you what it ran before the fans.