[tor-relays] total relay bandwidth

Hi, (rather new relay operator here, so excuse me, if this is a dumb question) I just saw this (https://metrics.torproject.org/bandwidth.html) graph, which shows that the advertised relay bandwidth in the whole network is more than double the actually used bandwidth. While it's certainly nice to have a bit of breathing space to absorb load spikes, I'm wondering, if new relays (i.e. non-exits) are actually helpful at this point, or if they simply don't make a difference. Am I missing something obvious? Thanks, Jens