I dunno, many times things are decided quick and need to be done quick. Also 1 second on a 32 core ryzen could be days or weeks or months on low end equipment. And 15 seconds on the high end equipment will be simply too long on low end.
But to do some work for the network where things even out a lot due to routing lags might be the area to look in rather than cpu usage. CPU usage is electricity waste and if we want 100K token transactions per hour/day over the network then multiply the electricity use for one machine by 100K and it then becomes significant. But if work is done for the network, like helping audit spending then its minimal work and takes enough time to minimise spamming, while doing work for the network that has to be done anyhow.