Vibrating panties give people like the excitement of having a party in their pants or dress, so to speak, when they're out in public. It's a great way to experiment with exhibitionism while being discreet.
And they can add a fun layer of dominance/submission if you use a pair of remote control vibrating panties egg vibrator with a partner and allow them to surprise you with new vibration intensities.
Vibrating underwear can also be a great accessory for private time too.
"During oral sex, strap-on play, or manual sex, wearing a vibrator allows you to experience being stimulated simultaneously by your partner and the vibe. Plus, if you don't have to hold onto the vibe, your hands-free for ~other activities~. (Related: 10 Different Sex Positions to Spice It Up Tonight).