Slade
[14] Master
I use it as a safer alternative to 1B at that tip-of-66A range where the opponent is close enough to connect a dash-in throw, but far enough to be able to evade 66B by backdashing. Like you said, it won't deter sidestep to Algol's left at all, but that's what I use to open up the opportunities to get 662A/661K pressure going.66A+B doesn't have a huge role in my Algol play. I keep thinking that it's something worth looking into more closely, but I generally find that I can resolve situations more reliably with 66B, 22A, 11K, etc, so I'm uncertain of where I'd shove it into the lineup. Plus little characters walk around it all damn day.
66B is a more rewarding option, but I see a downside in having to physically close the gap to ensure that the opponent can't backdash out of it, whereas 66A+B just lets me sling a bubble at them to cover my ass.
Neither are particularly effective at discouraging lateral movement, but it's a nice perk when 66A+B's dumb right side hitbox works in the Algol player's favor.