It is not as if the thing could be standard issue but what I am saying is I am sure that there would be plenty of scenarios where such a device could change the outcome and thus would be a good investment. The thing about war is that it is unpredictable, the army that adapts and takes the latest technology into account has a huge advantage. Being able to develop or anticipate new types of warfare are essential to the success of any campaign even our best games and simulators are a joke when compared to the unimaginable ways that humans can come up with to destroy one another. Think solders on skateboards sounds funny lets have a look at the past:

Unites States invests millions to develop a weapon more powerful than thousands of a single bomb put together.

Allies develop a special blend of ice called piecrete that they planed to use to build giant floating battle islands across the world.

Troops could be given a large sheet in the form of a circle that is attached via rope to a backpack and then thrown out of plains to attach a position by surprise.

Instead of standing in a long line and then attacking one individual unit in 1v1 combat regular people can be trained to hold a spear and simply stand in place with a shield and attack as one unit (Development of the phalanx, first used against Sparta)

Equip bats with explosives and lure then to key structures though the use of high frequency sound waves. Developed by Marines with a special congressional funding in WWII.

Instead of building high walls construct shorter thicker walls with angled sides to repel cannons

Get on a horse and then using a long metal stick hit other people at high speeds without getting killed.

Spy on enemy harbor by placing a clay pot upside down in water and having it held underwater by 4 rocks. User then walks around underwater for short times and also collects additional air by use of snorkel when at lower depths. (Punic wars)

Computer invented to better calculate accuracy for artillery later used to decode enemy encrypted transmissions.

A ship that can go underwater and attach bombs to the hulls of other ships (Civil War)

Putting a human in a big rocket and landing him on the moon.

Building a ship out of metal or a materiel that does not float.

Putting a flame thrower on a wooden ship.

Creating floating platforms so that ground troops can battle at see.

Developing M&M candy so pacific divisions can have candy that melts in the mouth and not in the sand.

Placing a pice of cloth around a musket ball to improve accuracy.

Using an armor plated vehicle to storm trenches

Weaponizing the gas given off when one tries to make mustard.

Using lazes like in the movie starwars to blow stuff up like missals.

Others that I can not think off the top of my head.