Speaking for myself, this is why COSMIC is appealing:

• nice middle-ground between oversimplified and over opinionated GNOME and KDE complexity
• both floating and tiling are first class
• Wayland native (no legacy)
• pushing DE innovation
• commercially backed
• written in Rust
• attractive
• fast

I also love that it is driving Smithay and Iced which matures the foundations of other great projects like Niri and even RedoxOS.