Yes… those units are gaining traction... but not as the main sparkler units. The batteries won't last the entire event in real life applications. If you're doing it just for first dance than having these units is fine. But if you're like me and shoot em up during the dancing portions, than having the wired ones are a must. The dj's using these are using them in conjuction with wired ones mostly. For example... they'll have the wired ones by the stage area, and then these portable ones opposite the main ones on the dancefloor, kind of like the photos you shared. They are a tripping hazard so I'm a little skeptical on them still especially if you have a photographer or videographer who like to move around a lot and not aware of their placement. Or if you have dancing on the clouds... they might not be visible to others in that moment. That's not to say I won't get somehting like this... I'm just waiting to see how venues receive this.
Sonic... the videos you see of sparklers catching things on fire are the real sparklers... while there is a heat element in the box, the sparks comes out cold to the touch (under 70 degrees). As far as upselling... I have them on about half of my events and made my money back and a lot more very easily. This year alone they generated over $10k in profit.