I agree, certainly at the national and provincial level. I know it has been piloted in some municipalities but, although municipal government more closely touches the day-to-day lives of most of us roads, transit, garbage, etc.), it is not the foundation of our liberal democracy. I have a hard time envisioning a foreign entity, or even a well-heeled developer going to the extent that would be required to hack a municipal election (there are far easier ways to exert that type of influence as we have all witnessed over the years). There is a lot more at stake with the more senior governments.
Online voting at the national or provincial level would require a level of robustness to ensure credibility that I don't think is currently achievable.
Even our mail-in procedure involves a process initiated by the voter which I get the sense is much more regulated than at least some of the US jurisdictions.
For all that at stake in an election at the national or provincial level, given advanced polls and accommodation for those that require it, a little effort on each of us every few years seems little to ask.