The larger the area of a radiator the more directional it is. This is why tweeters are made as small as possible. An infinitely small sound source would radiate equally in all directions and have perfect dispersion; this is why small speakers can "disappear" more easily than large ones. The smaller the drivers and the closer they are together the more they act as an ideal "point source". On the other hand the smaller the speaker the less air it moves so all speakers are a compromise. Low frequencies are essentially non directional so woofers can be quite large but the farther the drivers in the speaker are apart the farther away you have to be from them for the sound to properly integrate from the various drivers.
What is the point of point source?
I often read reviews of equipment that praise whatever is being reviewed for being a point source. I read this as a focused narrowly defined area that the music eminates from. I prefer the image of an "outside the speakers" soundstage that is often referred to. So why is point source a positive attribute?