Yep, all of the above, not to mention it would be brighter.
It's the same as the reason why a person would buy a1W laser in the first place, rather than a 100mW laser for example.
You should take a look at one of the threads circulating now that show styropyro's insanely bright "40W shotgun laser"; he probably built it for one reason, because he could.
It gives the user a wider range of capabilities.
Same as getting a high end muscle car verses a little around the town car or a 7mm magnum rifle verses a lower powered .22 rifle.
If you need more power for the task at hand, you will have it if you get the higher powered model. Of course you have to use it safely and wisely as it is a powerful tool.