Wow Barbara, that's my "Did you know" too!.... I've been ironing tissue paper as long as I can remember. I learned to iron them because I sewed clothing for many years and always ironed the tissue patterns whenever I used them.

Just don't steam it. lol
I use tissue paper to make patterns for kids clothing. That way I can make the same pattern in all the different sizes without having to cut the original!

You can also iron wrapping ribbon. I've done this for years. You can even use a warm curling iron to smooth the ribbon. Iron the paper, iron the tissue and iron the ribbon for reuse. No wonder I haven't put my ironing board down in 20 years.