I don't think I've ever played Asteroids in its original form. Do the shots actually sparkle and flare like that, or is that just a camera artifact?
Compared to asteroids in a MAME emulator the real display is way different.
It certainly does have that effect, but you're right in that it's not quite that pronounced.
I spent a lot of time playing Asteroids in the arcade growing up (that and Tempest). I have a physical problem with my left hand so I found playing a lot of later arcade games that required a lot of very specific movements of the joystick difficult so I kept coming back to those two because the left hand control was basically just a dial.
The shots in particular are extremely bright. Perhaps the cathode ray sits there slightly longer than for the other lines so that it's brighter.
I have a lasting impression of just how different the screen looks from modern displays. The combination of high contrast, light bleeding and the long image persistence makes it so different to emulation.