"
Residency" for tax purposes is separate and apart from "
residency" for other purposes (even though there is considerable overlap in relevant factors, and each can be a relevant factor in regards to the other).
Moreover, in regards to qualifying for various kinds of benefits, those can involve eligibility requirements that combine other elements in addition to residency. The Ontario Health Insurance Plan (OHIP), for example, requires ACTUAL PRESENCE in Canada (for 153 days during any 12 month period of time) in ADDITION to being a "
resident" of Ontario.
A person with just about any ties to living or working or obtaining income in Canada can declare they are a tax resident of Canada with almost NO risk Canada Revenue will make inquiry otherwise, let alone conclude otherwise. But, again, qualifying for various benefits, credits, deductions, and so on, often, if not usually or nearly always, depends on more than just being a resident for tax purposes.
And of course being a tax resident of Canada does not preclude another country from treating the individual as a tax resident of that country.
Leading to . . .
It warrants keeping the information you referenced, published by the Kalfa Law firm, in context. It is about avoiding being treated a resident for tax purposes in multiple countries, which otherwise would typically result in a substantially greater tax burden.
If the circumstances are such that an individual might be considered a resident for tax purposes in more than one country, most countries (nearly all?) will have NO problem with the taxpayer filing a return and paying taxes as a tax resident in that country EVEN IF they have also filed a return and paid taxes as a tax resident in another country.
Thus, for a taxpayer who files a Canadian tax return as a resident of Canada, for tax purposes, there is virtually no risk that Canada Revenue would disagree. This does not conclusively determine eligibility for benefits, credits, or deductions.
Where the CRA gets involved in determining if a taxpayer is a tax resident of Canada, or not, is in regards to individuals who file claiming they are not a resident of Canada for tax purposes, or who have failed to file a tax return when the CRA has reason to believe they should have.
The Annoying Greyness of Who is Resident for Tax Purposes:
This is largely the product of how complex the circumstances of real life can be for many, many people in a globalized economy in conjunction with very open borders and the prevalence of people with status to live and work in multiple countries. The variables are many, subject to all sorts of contingencies and conflicts. And there is no shortage of individuals who will go to great lengths to more or less game the system, to not just avoid tax obligations (legally) but to evade them contrary to the law and rules.
Ultimately there are so many variables that, in complicated cases, simple rules cannot adequately dictate tax residency with any degree of reliable certainty. For those with complicated situations, as
@owleroz suggested, best to consult with qualified tax professionals (and this does not include those out-of-the-box companies).