It works, as far as distraction (at least) or temporary compromise of vision. No one said you must remain in one place while a perp/active-shooter locates you. No one said the light must be kept on for more than an instant. And no one said it is a primary tool, or even a tool to use to the exclusion of others, or even a tool that cannot be used 'in conjunction with' other tools.
Incidentally, it helps you to ID things/people at night, and, under some circumstances, if used judiciously, it can deter the approach of opportunists looking for 'cues' (you see them, they see you, they see you see them, they see that you see that they see you

).
Beyond the fact that local/State law makes carrying an 'effective' knife less practicable, the size, power-levels, and cost of 'tactical' flashlights make it a possibility not to be ignored, and are no more burden than an extra mag or speedloader to have 'on-hand'.
I had a first-generation type strobe, years ago. IMO, not a fast enough flash-rate. Of course, I compared it to my Chauvet (entertainment lighting), which has a variable rate strobe that's
significantly more powerful. I'm sure today's hand-held strobes are vastly improved. But even the basic flashlights (AA or AAA) can get lumens from 135 and above which is sufficient to annoy another's vision, cheap to feed, weather-resistant, and usually of a reasonable impact-resistant material like aluminum.
Local trainer in my neighborhood, Roger Phillips (Suarez Int'l), swears by the technique, has written some about the use of the flashlight, here:
http://www.warriortalknews.com/2011/...-the-hand.html
(And, incidentally, this philosophy has some relevant comment for threads here re: pocket-drawn j-frames and the primary/secondary firearm issue, speed of draw, and capacity)
Though I'm no operator, I've always appreciated the advantages of a light, even if labeled a 'tactical' light. I still have a mini-mag light (now a back-up light in my wagon) that I bought almost 20 years ago for a trip to South America. If you can find a place to put it, not too much downside.
I usually carry one one a lanyard, at night (easy and fast out of the 'weak-side' pocket, reverse-grip with thumb on tailcap).
I'm currently using an LED Lenser P6 (2 x AA), maybe 35 or 40 dollars.