A visa extension and leaving and reentering on a new visa are two different things. I know it sounds weird if you haven't lived the visa life, bc it seems same-same. But it's all about a country mitigating risk. The biggest risk is overstaying a visa. In most countries, that's how undocumented residents primarily enter. They often hedge their bets by being very restrictive about what you can do on each specific visa. If you're there to visit family or go to school, they don't want you to be working. If you're there to work, they want to monitor who you're working for and how much you're making.

Someone extending a visa is saying "hey, now's not a good time for me to leave." Versus someone who leaves the country when they're supposed to saying "hey, don't worry about me. You can get me out when you want me gone".

You'll often see this just baked into multiple entry/long-term visas too. Growing up, my family had to leave the country every 7 years for at least 3 months, iirc. You go "home", reapply, and then go back in for another 7 years. I think Kuwait has a multiple entry business visa that's 10 years.

Even with tourist and visit visas, some countries will let you leave and reenter infinity times. A lot of expats live their lives in 3 month increments. Most countries, though, will eventually start to look at the frequency of your visas and determine that you are not, in fact, using it for the purpose you stated.

Which is what will trip Chantal up eventually.