They might have a great technological solution or expertise that the acquihiring company needs. Thus they might be paying for the technology instead of spending time and resources trying to develop it themselves.
That's not quite an "acqui-hire", though, that's a technology purchase.
"Acqui-hire" has a strong implication of, "we don't need your technology, and will likely discard/discontinue your product... but we want your engineers, as a cohesive team with relevant domain experience."
In that case the acquiring company would be coming to them. If there is a pinch point that bad that an unproven technology would be implemented before it has traction, any wind of the technology to fix it would draw mice.
"Acqui-hire" has a strong implication of, "we don't need your technology, and will likely discard/discontinue your product... but we want your engineers, as a cohesive team with relevant domain experience."