Yup, but as Chris says this allows all those lovely LTM lenses to be used on your M mount cameras. I have, thanks to an inheritance, a digital Leica M Type 240. I own almost no M mount lenses but I own many LTM/M39/screwmount whatever name you want to use lenses and they all work fine (well, unless they're from the former Soviet Union then they need someone like Sonnar_Brian to gently tweak them) and many of them - my Cosina Voigtlander Nokton 50/1.5, Canon 50/1.4 & Chiyoko Super Rokkor 50/2 - are my favorites and world class lenses. Look for Nikkor 50/2 and Canon 50/1.8 as well - both are easy to find, reasonably inexpensive and glorious. Just make sure they are in good condition - after 60+ years that's not always a given.
Buy them and enjoy them. They make photography more fun 😀