This is potentially good news for anyone in Canada wanting to travel to the Caribbean this fall or winter, although they will still face a 14-day quarantine upon their return to Canada, unless the government suspends the Quarantine Act. It will be interesting to see how many Canadians will actually want to get on an airplane for 3 to 5 hours while the pandemic still rages. That, combined with the ability to get the Covid tests some islands are requiring, may be the bigger factors affecting travel in the near future.
Flights to many of these destinations were suspended originally because everyone here was in lockdown and no one was travelling anywhere, unless it was essential. Plus, many of the Caribbean countries themselves shut down anyone being able to travel TO their countries. Finally, I'm not sure where the magazine came up with the characterization of WestJet as a "leisure" carrier, since that is definitely a misnomer.
WestJet is one of our two mainline airlines; the other being Air Canada. It started as a "discount" airline, but rates today between WestJet and Air Canada are often fairly comparable. It does have a subsidiary called WestJet Vacations that offers leisure travel packages, but it still uses WestJet aircraft. This is no different than someone flying on an Air Canada flight arranged by Air Canada Vacations.
Both airlines may offer some seasonal, leisure routes, or increase flights and capacity to certain, seasonal or leisure-focused destinations at peak times, but neither airline could be considered as a "leisure" carrier. Sunwing Airlines and Air Transat are the two primary, international charter or leisure carriers based in Canada.