I assume steri-strips are akin to butterfly bandages? If so they do work well but have a tendency to scar.

Steri-strips, as Mark says, are indeed the biz. Whether they are the best thing to do depends on the situation. As Mark suggested, they are best for a nice clean slice, and best if it is an angled, flap laceration where you can use the steri-strip (more like a row of them, commonly) to "approximate the wound edeges" -- pull the flap edges together -- and where you have a good contact surface underneath (as opposed to a straight-in laceration where you have to work harder to keep the edges together).

Once you have decided not to suture something the opportunity to do so is gone after a day or two. Given that steri-strips always have a higher chance of pulling apart and scarring, folks are generally more apt to use them where a chance of failure/scar is less problematic. Less likely they'd use 'em on a face if cosmetic outcome is important (like somebody better looking than me!), especially if it is on a tough spot.

Plus, foreheads and thereabouts can get oily causing the strip to come loose too early (or maybe the person can be trusted to reapply a few correctly, or they are in a spot where the person couldn't reach...), and it can be hard to clear away/prep a nice, unhairy spot for the ends of the strip to stick to. To maximize chances of success, we always used the nastily sticky tincture of benzoin.