Way better UI, no hussle with configuration, flatpak support is seamless. Very good experience over all, such a smooth game adding -> configuring -> playing experience.
I agree with FarLine that bottles is way better than Lutris. I still believe Heroic launcher is better than bottles for Epic/GoG/Prime games, but Battle.net and sc2 for example was so much easier to get up and running on bottles compared to lutris!