You should point out that the long range weapon doesn't fit six tubes into the same footprint; it fits one super chunky missile into the same launcher. The long range missile necessarily has to be much larger in order to hold enough rocket fuel to achieve that kind of range. It's not as if the long range one also comes in six-packs. See this photo of the long-range version:

https://api.army.mil/e2/c/images/2018/04/15/513843/original.jpg

The US only has a very limited supply of the long range HIMARS launched missile. Ukraine honestly could do better to have 6x as many missiles of the shorter range version for beating back the Russians. But a few of the long range ones may be useful for hitting some strategic targets, like that bridge to Crimea, which would have an outsized impact.