The Survival Knife / Thermoblade is a vital tool that empowers the player, and feels like an invaluable instrument in your arsenal to harvest plantlife, fauna, and smaller critters that roam about the vast oceans.
The Multitool doesn’t offer the same feel good sensation as our good old reliable, which was a stable of the first two games. It feels clunky in comparison, and is less cool and engaging to utilize throughout the game.

Yeah, well, that’s just like, your opinion, man.
I love the multitool and although it can’t instantly cook fish, it’s just way cooler as an idea in my opinion than just… a knife. I don’t even know what you mean by less cool and engaging since SN2’s switch axe does everything the knife did in SN1 gameplay-wise (apart from killing and cooking fish) and arguably even more since there are more resources that explicitely require the multitool than there were for the knife.
Also like, why do the same thing when you could do something different?