If it comes to the security a hashing or encryption algorithm provides, we never know the full story. There's that part that we (respectively the public research) understand and can reason about, but we also know that there might be weaknesses we do not know about and though we can't reason about things we don't know, still that unknown part is relevant AND is affected by certain parameters.
If you for example have two symmetric encryption ciphers, say AES-256 and TwoFish, which conceptually should provide about the same security, which one would you rather trust?
AES-256 is much more widely used than TwoFish. This means there is a much higher incentive in breaking it (and probably much more resources are poured into achieving exactly that). That might be an argument why to prefer the underdog. On the other hand, one can also argue that much more public research is going into AES-256 for the same reason and therefore IF something was fundamentally broken, the chances that it would be publicly known are higher.
Or do such properties cancel each other out anyway and thus adoption rate of an algorithm is of no relevance to security considerations at all?
What would you put more trust into and why?