>>40663596It's likely that they're needed for the food chain and environmental equilibrium. The ones we deem bad like snakes are to punish men or have as natural "evil", although in modern times we have learned to use them too, e.g. taking a snake's venom for an antidote.
The Ocean is the big mystery as it is huge and we don't know most species in the deep levels.
Lastly one can argue from beauty, that the complexity of the world including them is to be a signature from God.
For by the greatness of the beauty, and of the creature, the creator of them may be seen, so as to be known thereby [Wisdom 13:5]