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.
It's hard to balance anything until they explain why they did it. So far they claim they aren't at liberty to share but claim it was bad enough to make a very unprecedented move like this.
... and Bytedance will not have any recourse if Canada bans the app.
TikTok is still going to collect that data, and it will be kept in China, far beyond Canada's reach. To remove concern over the data, I reckon you'd go about it backwards: Get rid of the app, which is up to no good. Keep the offices, so that they can be spied on or forced into transparency via the courts.
This makes the most sense if Canada expects (or has) Canadian troops secretly deployed somewhere. And that is one sobering thought.
I'm not sure I follow (maybe there's other details you know about that aren't in the article, or I missed it). I don't think there's anything preventing a Canadian company from paying a foreign company for ads? In theory I'd have to self-assess PST maybe but I order stuff (both physical and digital) from foreign companies with no Canadian presence on a pretty regular basis.
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.