As Russia's circumstances and prospects continue to deteriorate, the terms will get better and at some point a deal might be made. That will likely not be the case, but talks of any sort will provide a better understanding of Putin's frame of mind and intentions. And that is what Putin hopes to learn about the US and NATO.
Article "The Heavy Clouds of Peace" by Nicolas Tenzer
The author's grandfather died in WW I and his father fought in WW II. Due to that experience the only thing his father was truly afraid of was "peacemongers" because therein lies the road to (great) war.