Okay, let's assume that we have two different lights, both of them producing the same amount of lumens. The difference is that one is a flooder with wide beam profile, while the other is a thrower with narrow beam profile.
Scenario 1: Long distance spotting. With a flooder, you'd have to get close, while a thrower means that you don't. With a flooder, you have to walk closer to the area to get proper illumination. With a thrower, while you get less viewing angle, you can just sweep the area in multiple passes with your hand.
Scenario 2: Looking into a dark environment from a well-illuminated area. Let's say that you are standing outside in a sunny day, and need to look down into a well or into a large warehouse. Because of the exterior illumination, your eyes will not be adjusted for low-light environment. A flooder isn't going to illuminate much of anything far into the dark environment that you need to peer into, but a thrower can effectively punch through the background light pollution and allow you to see what's inside.
Scenario 3: Close-up inspection of surface covered in dark material, such as paint, grime, etc. For example, you are inspecting pipeline that's covered with years of black gunk. That black gunk is going to soak up light very efficiently, and a flooder just doesn't have the punch to light the surface up enough. With a thrower and its highly focused spot, you can be damned sure that it's going to light it up, albeit small portions at a time, but nevertheless allow you to see what's on the surface.
Scenario 4: Dazzling. Don't even kid me on this one. A thrower with its concentrated beam is much more effective at blinding people and critters than a flooder.
In simpler terms, it's like comparing a pellet to a slug. The former has a wider dispersion and is better at closer range, but a slug is going to crush through objects farther down the range.
This is only true if the light use the same lumens.
In reality, they typically don't, as a floody light NEEDS more lumens to lit up a target in an equal manner. This means to throw the same as a concentrated beam, a lot more power is required.
If you NEED to see a large area at once, for example, when sweeping an area with a tight beam takes too long (Say a few seconds), it can give what you are looking FOR a chance to SEE YOUR SWEEPING BEAM.
Think back~ to every prison/POW break out out movie...when the search tower search light is sweeping around looking for the escapees...they see the beam coming, and duck/hide...then run for it as soon as the search light beam passes them....safe in the dark surrounding it.
If you need to see very far, for efficiency's sake, a thrower is designed to do that more efficiently than a flooder. Too much light in the foreground reduces your ability to stop down your eyes and see further off into the darkness.
If its a powerful flooder with say 400 yards of flood light...well, you can still see into the darkness 400 yards, even if you can also see everything on the way out to 400 yards as well.
To GET a flood light that CAN throw 400 yards, its NOT going to fit in your pocket. (Unless you might carry a few coke cans in your pockets, etc...) Its typically going to be holstered at least...and have a lot of cells to power it.
To have a thrower than can reach 400 yards, it can be pocket sized, as it needs less power to project its smaller beam in a more dowel shaped pattern.
A floody Fenix TK70 shot zoomed at a tree ~ 405 M away
A tight throwing Deerelight Aspherical at same tree
Essentially, the Deerelight is a very good small thrower and the TK70 is very good large flooder. Obviously, is SEARCHING for something way off, at that range, the TK70 will find what you are looking for BETTER than the Deerelight.
BUT, do you want to CARRY a giant heavy light all the time, or, would you rather have a smaller package?
Of course, you can also get large throwers, and a large head can help to throw a very well focused long range beam...so, again, for the same lumen out put, the thrower will still see further...just less at a time.