A framework is a trade, not a free win. It's worth naming both sides plainly, because the choice is real and it goes both ways depending on the project.

What it gives you

• Speed. The components exist. You assemble instead of build, and a standard interface comes together in hours, not days.
• Consistency. Every button, card and input already matches — a coherent design system you didn't have to design. On a large app built by many people, that consistency is hard to keep by hand.
• Solved problems. The responsive grid, the cross-browser quirks, and often a baseline of accessibility are handled by people who specialise in exactly that.
• A shared vocabulary. A new developer who knows Bootstrap can read and extend your markup on day one. On a team, that leverage is worth a lot.

What it costs you

• Weight. You ship the framework's whole stylesheet — and often its JavaScript — even though you use a fraction of it. It can be trimmed at build time, but frequently isn't, and a page that could be a few kilobytes of CSS becomes hundreds.
• Sameness. Frameworks have a recognisable default look; "it looks like a Bootstrap site" is a real critique. Standing out means overriding the defaults, which means fighting the framework you brought in to save time.
• Abstraction instead of understanding. You learn the framework's class names, not CSS. That's fine until something breaks or you need something it didn't anticipate — and then you're debugging a large stylesheet you didn't write, without the fundamentals to reason about it. This is precisely why this track taught you CSS first: so a framework is a tool you can choose, not a crutch you can't see around.
• Markup noise. Component and utility frameworks alike push a lot of classes into your HTML (class="d-flex justify-content-between align-items-center mb-3"), and the meaning of the page can get buried under the styling.

The shape of the trade

A framework buys you speed and consistency and charges you weight, control and understanding. That's not an argument against it — for the right project it's clearly worth it. It's an argument for making the trade on purpose, with your eyes open, rather than reaching for one by reflex because it's what you were handed first. The next step looks at a second kind of framework that shifts where that trade lands.