I base this on absolutely 0 military experience BUT

Could be a distraction vessel to draw fire

Could be to give Russia a chance to use countermeasures and evaluate their effectiveness + come up with next Gen drone to mitigate current countermeasures

Could be that it is impossible to get a good video from a drone bouncing around in the water and they wanted to make contact with areas that ensure sinking

Could be a test to see how much punishment the drones can take while maintaining combat effectiveness

Could be that it's pure chaos and neither side has a great strategy aside from do/do no explode if possible

Either way, this footage is wild! Give em hell Ukraine!!

I imagine a bunch of drones zig-zagging around your ship in the middle of the night are much less predictable and harder to hit than if they are coming at you fast but in a straight line. You are bound to lose track of one of them in the chaos. There's also less of a risk that the drones blow each other up when one gets inevitably hit. Plus, there's probably a significant delay in the controls on top of the difficulty of steering an unstable watercraft like this.