Support GOG, support no DRM.
To the parents question, it is better to use GOG if you care about DRM.
Sometimes the Steam version is qualitatively better because the publisher/dev has supported the Steam version with more updates. Often the updates do turn up on GOG, but it's possible there is a delay.
Recent example: https://store.steampowered.com/app/3357650/PRAGMATA/
https://www.pcgamingwiki.com/wiki/List_of_DRM-free_games_on_...
Mad Max Middle-earth: Shadow of War Deus Ex: Mankind Divided Yakuza: Like a Dragon