The computing work secures the block chain. That's the opposite of wasted.
In your computation certificate proposal, would you be able to trade certificates? If so, each grid network would be able to trade counterfeited certs (generate certs for which no work was performed). If not, it isn't a currency. Not to mention that exponential increases in computing power would cause the system to be inflationary, where a goal of bitcoin is to be deflationary.
> In your computation certificate proposal, would you be able to trade certificates? If so, each grid network would be able to trade counterfeited certs (generate certs for which no work was performed).
Yes, you'd be able to trade certificates and portions of certificates. The point is that the certificates have some real value too since they are essentially vouchers for more computer time on the grid network (some percentage of the time you contributed in the first place), that's why a grid provider wouldn't want to distribute more certificates than necessary.
There are a number of ways around the inflationary problem, the simplest would be for the certificates to be in whole grid computing seconds, so as the grid grew larger and more able, the certificates would increase in value at the same rate.
By the way being deflationary is a really bad idea - it stops investment and shrinks the whole pie of economic activity. Perhaps it wouldn't matter too much for a parallel currency, but for your main currency it'd result in massive unemployment.
In your computation certificate proposal, would you be able to trade certificates? If so, each grid network would be able to trade counterfeited certs (generate certs for which no work was performed). If not, it isn't a currency. Not to mention that exponential increases in computing power would cause the system to be inflationary, where a goal of bitcoin is to be deflationary.