Warp drive work by scanning the gravitational waves that correspond to the target and creating a warp tunnel in it. BM are just a representation of the triangulation of the surrounding waves, that’s why you can’t create an arbitrary BM : you need to be there , or be given the signature.
A point works by simply sending surrounding signatures to the warp drive, making it unable to acquire the tunnel. It’s like you look at your GPS, and suddenly all the surrounding places are just on top of you : you know it’s not correct but your navigation system just does not work anymore. Having several acquisition systems (warp strength) allows to still acquire the signature by dissipating the noise and adding more sensors.
Bubbles work in a totally different way : they disrupt the creation of a tunnel going through them(stop) or aiming at them (drag)