I don't understand the question. Coins can be exchanged for goods and services in the usual way. Doing so resets their age to zero, so the receiver can't use them as mining stake for a while.
Is there any economic benefit at all to the network from such a mining? The transactions are practically handled centrally, like in banks(?)
No, it's distributed. (Unless you think Bitcoin is also mined centrally, due to a few mining pools having a virtual monopoly.)