Yeah it is interesting. Fans are basically stat scouting and throwing in some age vs. level analysis and very light scouting based on velocity, height/weight and what prospect sites tell us. Prospect sites use the stats, plus actual scouting and whatever insider knowledge they can get their hands on.
Actual orgs are doing everything the prospect sites are x 100. But even further than that, when they trade the player they are also revealing the market value of the players involved in the transaction. We think we know the market value but we really don't until we see a player getting traded or signing a contract.
Doesn't mean the teams are always making the right moves, but it does reveal what the players are worth in the marketplace.