1) חזל instituted חזרת הש״ץ (the חזן’s repeated שמונה עשרה) because back then many people didn’t know how to daven 🚫🧠
- Therefore they could be יוצא with the חזן✅
2) We still say it nowadays as there is always a chance there will be someone who doesn’t know how to daven but is embarrassed to say so 😶🌫️🤐
- Doesn’t mean you should make sure to have a person like that in shul