Many states around the world issue a national ID card to allow for one common efficiently standardized ID and database. If Canada were to do so, I could see two possible solutions:
1. Establish a new national ID card, or
2. Make the Canadian passport a compulsory ID for all that would double as our national ID card.
I'd personally prefer the latter option just to remove redundancy. Only one problem with the latter option would be that permanent residents could not get it, so they'd need to use their permanent resident card and foreign nationals could just use their national passports when in Canada.
Either option would allow police, CRA, and other agencies to rely on a common standardized ID and database for their work (or at least more so than is now the case) which could save the taxpayer much money in crime prevention and investigation and identification, voter ID, maybe even provincial health ID and a wide range of other purposes.
This could were super great!