I don't understand it either. I weirdly feel they know it won't do well so they can release it now, say it got lost in the shuffle of the summer season, and then have it ready to go on
Disney+ for the appropriate time it should've been released. Almost like it's being released to feed a content hole on Disney+.
I would argue though you're dealing with movies that have star power built on an existing long running, iconic franchise (Barbie), a big time director who makes appointment viewing films, and a movie that appears to fill a demo that's being overlooked. I will say WB/Mattel did a much better job of marketing Barbie to look interesting to the average movie-goer. Disney has a huge problem with making compelling marketing.