It would certainly make taking Inferno's B site much easier.
While it's highly unlikely that Fortnite's building mechanic would ever officially come into play in CSGO, crazier things have happened. Users have created tower defense maps, horror anthologies, and even recreated Golf It! within CSGO's source engine, so it's not that crazy to think that someone with enough time and effort could bring a full crossover between the two games into reality.
User maps have also created some of CSGO's most memorable moments. Several years ago, streamer Michael "shroud" Grzesiek played hours of maps created by users, leading to some of the funniest clips found on Twitch.
User-created maps are a huge part of CSGO. Players have created countless practice maps to help users hone their aim, movement, and grenades. There are retake servers where players continually practice attacking and defending planted bombs.
CSGO's battle royale map, Jungle, was created by a member of the community.
While it really is unlikely that building will ever come to CSGO as an official feature, the game's players undoubtedly dying for new content. It's been months since the end of Operation Shattered Web, and Riot Games' new first-person shooter Valorant is currently stealing the show. With few CSGO events taking place over the July player break, all it takes is one person creating something insane to capture the minds of CSGO's players.