Virtual fireworks are fireworks rendered on screen. The fuse burns, the shell lifts and the burst opens, but nothing actually ignites. A virtual firework is all light and no fire, which is why it works anywhere you have a screen.
That is the big difference from the real thing. A real firework needs a match, an open space and a clear sky; it leaves smoke behind, makes a lot of noise, and is banned in many cities. Virtual fireworks need only a phone, a tablet or a laptop. There is nothing to store, nothing to clear away and no one to frighten.
The sound is real, even though the fire is not. You hear the strike of the match, the crackle of the fuse and the boom of each burst, so the show feels like the night it imitates. That is why virtual fireworks suit a room indoors, and why they are so easy to send to someone far away.