ByteDance will keep no data in Canada, will not employ any Canadians, will not report any information to Canadian authorities, and will have no reason to comply with Canadian warrants or court orders. (Or even judgments.) At the same time, all Canadians can continue to use the app.
On balance, this seems bad for Canada and great for ByteDance.
Canada has an extremely generous, massively exploited foreign worker program (it is actually one of the reasons this government is profoundly unpopular). ByteDance, like every other company, can unilaterally declare that they need to bring in an entirely foreign staff and get it rubber stamped. Given the company's alleged closeness with the party, using it as an easy vehicle to drop loads of intelligence workers of various sorts in Canada would be logical. Similarly China has a thing with running intimidation tactics against Chinese ex-pats living in Western countries.