In the Bitcoin industrial space most of us are of the belief that only the marginal value of the work matters for security.
For example, if you can combine mining the Bitcoin chain and calculating ads for google, and the Bitcoin mining pays $1 and the ad crunching pays $5, then this process is really only providing $1 in security. The reason for this is that the for the security of the chain we care about your lost opportunity to mine one chain vs another, which keeps you working to say on the eventual winning chain so that you get paid that $1.
It's also inaccurate to describe mining as not useful. It makes Bitcoin secure. This is very useful, at least to those of us who use Bitcoin!
From a practical perspective the general constraints on what makes a proof of work good for a system like Bitcoin (e.g. that it must be largely optimization and approximation free and that you can randomly generate instances all with roughly equal hardness and that it be cheap to verify) broadly exclude most classes of work you'd likely call otherwise useful.
In the Bitcoin industrial space most of us are of the belief that only the marginal value of the work matters for security.
For example, if you can combine mining the Bitcoin chain and calculating ads for google, and the Bitcoin mining pays $1 and the ad crunching pays $5, then this process is really only providing $1 in security. The reason for this is that the for the security of the chain we care about your lost opportunity to mine one chain vs another, which keeps you working to say on the eventual winning chain so that you get paid that $1.
It's also inaccurate to describe mining as not useful. It makes Bitcoin secure. This is very useful, at least to those of us who use Bitcoin!
From a practical perspective the general constraints on what makes a proof of work good for a system like Bitcoin (e.g. that it must be largely optimization and approximation free and that you can randomly generate instances all with roughly equal hardness and that it be cheap to verify) broadly exclude most classes of work you'd likely call otherwise useful.