Twitter is best used during a crisis, an emergency etc when you or those you know are caught up in it and you need updates or help. Its has become the first channel of choice on early updates from the authorities, people in the know or directly involved. Examples are London riots when people tweeted to find what to avoid, places open to buy food etc, Heathrow snow shutdown with thousands stranded......
Then you have Taylor Swift or updates from Professor ( personally this stumped me!)
Ps. Once you provide the phone number, it will back to normal. The US authorities are pushing the social media industry to do a base level KYC and the phone number or an altenate valid email completes the validation. If you have old accounts such as hotmail, yahoo etc, you will eventually get it. Real pain until you provide the validation.