Many open worlds in games are just superfluous, there to pad play time and add 'value'. They fill them with collectables or boring side quests where you follow detective vision markers that take you from hotspot to hotspot to make it feel more real, but like many in this thread have said the open world isn't actually used to make the game have a wider range of options except in some rare cases.
I never got why people were so against the MGSV open world, for me it was one of the best parts because it gave you the freedom to complete your objectives that you'd get from an open world but didn't fill it with mindless busywork on the way.
I really think immersive sim type games do better for me these days at really immersing me in an environment than open world games do, because having everything feel more handcrafted and placed makes the difference. Games like Prey and Dishonored give me the open range to decide how I want to approach something, as well as the depth of worldbuilding that they provide to really make you fee like part of the world.
the joke is, RDR2 uses many immersive sim elements, so far unseen in a AAA production and exactly why so many people think the game is "tedious".
sure, the missions are linear because they want to sell you the cinematic romp which is directed and choreographed, but many things in RDR2 are borrowed from immersive sims.
Besides that is RDR2 one of the most fascinating Open Worlds this gen, how someone could think Horizon or Ubisofts OW games with its icon plastered maps and checklist style themepark events is better than RDR2´s open world that feels like a real world is beyond me
For me, open world doesn't always mean it's sandbox. MGSV is a great example of an open world sandbox game.
this is also true