Not just in bullet, but in many lower level games (even rapid) these openings can be very effective. However, once a player's rating reaches around 900 or higher, they work a lot less well.
Do trap openings have a use?
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I like to play for opening traps all the time, my whole repertoire is build around gambits and traps. It works very well for me. I'd say I emerge from the opening stage with advantage more often than not, but that problem for me is I'm not able to convert but loose even if I'm winning in the middle game 
There are two kinds of opening traps:
1) Traps that arise in an otherwise solid opening, and can lead to quick wins (E.G. the fried liver attack out of the Italian)
2) Traps that involve playing dubious moves for the purposes of tricking the opponent into a losing line (E.G. Englund gambit)
No one could reasonably object to the first, so I'm going to assume we're talking about the second. Trap openings do have a bit of value. They can be used as a temporary patch for a hole in one's repertoire. They also teach certain tactical motifs. There's also an argument that if you get "free elo" you're playing higher rated games in your other openings and thus getting better experience in those.
The problem with trap openings is they're the empty calories of chess, and players can fall too in love with them. You might be able to get to rating X by memorizing some tricks, but without a solid foundation it will be that much harder to get to X plus 100.
I've been watching videos (like Ben Finegolds series on opening traps) on trap type openings, such as Fool's Mate, Scholar's Mate, Wayward Queen, Fried Liver Attack, etc for fun. And they are certainly interesting and enjoyable.
But are such 'gotcha' openings of value? Are they ever effective? And is it worth playing them in the long term? My gut feeling is that they may have utility in low level bullet, but that's about it.
Opinions?