Lutris furfils several roles that a bunch of .desktop entries will not.

• Its a list of games
• you can search it by title
• you can tag them
• you can sort them in different ways
• you can use wine for some launches, proton for others or native

although i don't use it, you can log into your steam account (i think also gog?) to get access to games from there.

Think of it, as a more of a plex/jellyfin library for games than a bunch of video files spread around your hdd. I don't want to remember which games are wine friendly and which need proton or are linux native.