SPOILER WARNING In post game you can use Wyrmslife crystals as currency to buy some of the best gear in the game, and a huge source of those crystals are 4 bosses in the overworld that drop 90 crystals each.

If you kill Talos yourself, a certain event happens in postgame and you only get to kill 2 bosses instead, which means a loss of 180 crystals you could use to obtain both a weapon and a chest piece.

To clarify, you shouldn’t try to stop Talos from reaching his destination. Even if it means he destroys part of the rest town on his way there

Edit: The people who are claiming to have taken Talos down early and still having the bosses doable are using the Preserved Medusas Head to turn Talos to stone, completely destroying him. This may be a good way of getting all the boss fights while still keeping the Volcanic Island town from being destroyed.