Here in India the plans do include free SMS, but there was a government imposed limit of 200 SMSes per day from a single SIM (this applied to retail consumers, not institutions that may want to send transactional or marketing messages). [1][2] Beyond that, the per SMS charge gets expensive. Though that limit seems to have been removed in 2020, [3] I’ve only seen plans that allow 100 SMSes per day.

Almost everyone in India with a smartphone uses WhatsApp. SMS is for receiving OTPs, transaction messages, marketing messages, spam, phishing messages, etc.

[1]: https://trai.gov.in/notifications/press-release/trai-extends...

[2]: https://www.firstpost.com/tech/news-analysis/200-sms-per-day...

[3]: https://indianexpress.com/article/technology/tech-news-techn...