Here's a more thoughtful and hopefully coherent reply.
To my mind, a sandbox offers the player some control over the strategic and tactical direction of play. Now, in a game based on the zit-covered, hormone addled, low stakes ass-world that is high school those decisions might be as minimal as which person to ask to the dance. As a game aspires to greater stakes, the potential impact of decisions offered to the player should also grow; there should be the possibility of different outcomes, and preferentially, different routes a player can take to reach objective. If the decision impacts remain effectively cosmetic, there is less sand in the box and more railroad tracks.
This game offers some minimal player input -- mostly cosmetic, but some early input tied to necessary resource collection, but even in this realm, essential resources are mostly either bait-and-switch/given to the player rather than being necessary to gather. (cash for tuxedo, 100K bank transfer, millions in extortion). The strategic goal is set in stone as is every meaningful tactical decision on how to reach it. Even the choice of whom to fuck is (mostly) assigned by the game with a few secondary possibilities dangled as extra tidbits.
These tracks become incredibly apparent when progress along a seemingly impactful line is held up by entirely inconsequential actions with a different party. I plan the heist with Robin. We strike the bank tomorrow (Tuesday) night! Except, tomorrow night when I try to go to the bank, I'm told I need to get an answer from Holly. What answer? I have a question? OK. Let's go talk to Holly!. Hmm, she's not in the house. Check the hints. Oh look, she sleeps at the pool Fri and Sat nights. Let's check her room Wed, and Thurs night. Keep going over every night even though I have a place to sleep because once I enter the house, I can't leave until morning. Nope! OK Friday, let's go to talk to her. Wait a minute, I can't go over tonight because reasons. OK Sat then. There she is! OK hmm, I'm not waking her up... I'm sniffing her feet? THIS is why I can't rob the bank???? Sun night! Time to rob that freaking bank! Nope, have to talk to Holly still! But I run away when she wakes up! Fine. Waste the next 5 days, check her room at night just in case -- nope! She's only there asleep at the pool! Fri can't go over. Sat can't go over. Waste the next 6 days. Fri can't go over. Sat can go over and creep on her some more. Ug. Fine. Waste the next 6 days. Fri go over, more creeping! Keep creeping until something different happens, I guess! Finally! I talk to her. OK I still haven't asked whatever question I need answered. Mon I finally find her in her room and ask the momentous and obviously critically relevant question... "How did my dad die?" Umm, what? OK fine! Can I finally, weeks later, rob the freaking bank now?
It's not a sandbox. It is a minimally interactive story where the player is allowed to somewhat reorder the chapters within constraints, but all of the chapters WILL be completed. Please note, this isn't a criticism of the game. Minimally interactive stories can be fun, but not when the player is told to expect a sandbox.