ok seriously, side-b has some very serious uses...
against predictable projectiles it's a great move... if a lucario is at high %'s (which often happens 'cause rob has trouble killing) and gains the advantage, lots of Lucario players will throw out the charged b move to zone, as rob can't air-dodge from the upb and he has to perform a move... while this is easy to avoid, it forces rob into a predictable spot, which is just in the other players favour
to stop this, a side B, though very slow to start and predictable, when anticipating this, will often hit luc or even kill because they aren't expecting it... if the luc does shield, he has the shield stun so he can't aggro. ledge you, and you are in a better position than had you not...
i'm using lucario as an example because he's one of the highest tier'd players with the great projectile, but obviously it works for all spammy chars...
secondly, after a fully charged gyro or some sever aggro pressure the opponent is often at low shields... it's well known that side-b is a great shield poker, and with the final hit with decent enough knockback it's a good option... again, if you use it in a predictable way, you will get punished (i'm pretty sure it can even be di'd out of before that last hit) but as long as you don't spam it, and you don't mindlessly carry out the attack to the full length it is a solid choice of move
thirdly, it's another attack... even if you watch OS he uses it occasionally... not in every scenario, but keeping the opponent on their toes, wondering what you're going to do next is key to rob. He's all about the spacing, and if you stick to just your "bread and butter" then a good player will quickly pick up on your habbits...
having another option to attack, with an odd momentum shift, and variable length... if his other moves weren't so good, this would seem like a great choice
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lol and while I'm at it I may as well say that dash attack also is a great stuational move... dtilt trip -> dash attack -> upsmash could mean an early KO, which for ROB is a blessing...
I think this tier list thing as a whole is a blessing and a curse because although it helps new players pick up on the better moves, it gives the false impression that the low/bottom tier moves are bad, and are always a worse option than the higher tier ones
I thought the little extend the arm and make that huge blocky fist was his only getup attack o_O
