I think the “get lots of input in a short time from a crowd with different semi-informed opinions” feature of prizes are hard to replace through other mechanisms. Some companies have built up extensive expert networks that they can call on-demand to do this, but that still doesn’t have quite the same agility. However, in those cases you may often want to compensate more than just the best entry (in line with the OP)
I think the “get lots of input in a short time from a crowd with different semi-informed opinions” feature of prizes are hard to replace through other mechanisms. Some companies have built up extensive expert networks that they can call on-demand to do this, but that still doesn’t have quite the same agility. However, in those cases you may often want to compensate more than just the best entry (in line with the OP)