Is buying followers illegal and why?

Buying followers isn't an illegal thing but it is against the guidelines of social media platforms like Twitter and Instagram. These platforms have developed stronger and smarter algorithms that detect easily if you have bought followers.

Tools like FollowerAudit will also identify within minutes that you have bought followers.

Once Instagram/ Twitter finds out you can get banned from the platform permanently.

So you won't be benefited from it. Moreover, bought followers won't be active and won't engage with your content (no like, share, or comments).