This is a genius move. WB was losing money shelving these movies. Tenet may of been it's sacrificial lamb, but it gave WB a template to go on in knowing that the international market is way healthier than the domestic. They also want to boost subscribers on HBOMax. So why not? They're going to make money from both ends with the little bit on the theatrical end, but a little bit on subscription side too. They see Netflix's success behind their movies they released on their streaming network which correspond with coming out in theaters, so they are on a "what do they got to lose" mode with their stagnation that has happened because of the pandemic.
The fans are going to be happy because they have a choice and access. They studio is satisfied because it is better to recoup SOMETHING than to lose everything. They know the writing is on the wall on theaters and want to jump ahead of the inevitable. They know this will definitely boost the number of subscribers and would appease the theater chain by having it in their theaters still. The only people who may not like this are the filmmakers themselves. Many them filmed their movies with the INTENT solely on the big screen. Not all of them are like Scorsese who accepted Netflix to release his last movie, and that's due to industry shenanigans that tried to compromise his creative freedom... but with that said, it may give filmmakers more creative freedom taking advantage of HBO Max which Zack Snyder was blessed to produce his cut of Justice League the way he want it.
I approve this move.