British council says "We use the past continuous for something that happened again and again. And they put some sentences below:
I was practising every day, three times a day.
They were meeting secretly after school.
They were always quarrelling.
However, when I examined these sentences, it seems that they have the same meaning with "used to so something". Grammar books say "used to do" is used for actions that happened in the past again and again. And now, I see that past continuous is also used for the same function - repeated actions in the past.
And in the above sentences, you can actually replace "was/were doing" with "used to do" without distorting the meaning.
I used to practice every day 3 times a day.
They used to meet secretly after school.
They used to quarrel, always.
So, can we say "the past continous tense" and "used to do something" both have same meaning when it comes to actions in the past that happened again and again.