It's not easy (or at least I don't find it easy) to express this idea naturally in English. The metaphor seems to be something like a robotic arm, or at least an extension arm, and that is what has led me to "extending the reach"; this is more idiomatic, I feel, that a noun phrase, and thus I would render "indispensable" as "play a vital role" (or "an indispensable role" or "an essential role").

This may at least provide a starting-point, and perhaps someone will come up with a convincing metaphorical expression in English.