What's your point? Synergy has real meaning as well. The problem is when concepts like leverage or synergy become goals in and of themselves. That might be something you'd expect from someone who's read a lot of management books, but you'd expect engineers to see these as means to an end.
While I don’t advocate the use of these terms in every situation, it’s hard to have all ends in mind and to carefully choose which tool should be applied to each end. That may be why these properties are used as goals. Easier to spot, easier to reason about. Basically, they are heuristics.
Reuse is leverage. If a piece of software (function, class, module, service, tool, whatever) is used for 1 task, it's not leveraged. If it's used for 10 tasks, that means the creation of the reused thing had 10x leverage: working on that reused thing created 10 times more value than working on something that's only used once.
It's not quite that straightforward as everyone knows, there are costs to reuse (abstractions (both lowest common denominator and leakage), more dependencies, higher maintenance costs owing to risk of breakage of multiple clients, etc.). But the leverage is very often real.