$3B is pretty small on the large scale. Especially when you consider the cost of adding them later (while it may not be paid for up front by the government, costs of doing construction, like closures, do add to gov't costs)

In normal human terms, yes, but 3B is only .08% of the federal budget.

Also, there is some economic gain from this activity...paying construction workers to install it, and whatever the end users decide to do with it. Is that gain > 3B? I don't know.