Many restaurants make lovely and delicious food... but their food is also expensive compared to preparing something yourself.

Convenience foods (microwave dinners, fast food) tend to sit somewhere in the middle. Cheaper then restaurant food but also both likely deficient nutritionally and not tasting good unless it's absolutely loaded with carbs, fats, salt, etc.

That cup of snot is most likely better for you then fast food and is a hell of a lot cheaper. Eating something like it could very well mean that you get to eat delicious restaurant food more often simply because you can afford to do so.

Restaurant food is comparatively expensive for many people. In my country (welfare state, high minimal wage), even takeout is generally much more expensive than a homemade meal. Not to mention food delivery to your doorstep; the cheapest Indian meal I can order for delivery, for example, is $43, of which the delivery charge is $13. That's insane. For $10-15 I can make a decent meal at home.

Restaurant food is also very often unhealthy. They add tons of fat (generally butter or cream) to make it taste like "proper restaurant food". Unless you stick to the salad.

And many "convenience" meals (frozen stuff, or souse-vide packets for microwaving, ready-made soups you just heat in a pot) just are not very good. I personally struggle to find easy-to-make meals, and often end up just frying some eggs or cooking some pasta with oil and garlic, just because I don't have the energy to make a proper dinner.