Repeating a sentence twice in a row during an explanation, is not spaced repetition at all. Spaced repetition means testing recall at increasing intervals, usually starting 1 day apart.

"Paris is the capital of France. Paris is the capital of France" -> not spaced repetition.

"Paris is the capital of France. [one day later]. What is the capital of France? [three days later] What is the capital of France?" -> spaced repetition.

And in fact, it's this plus practice where the real value lies in learning and memorising. The only purpose of an explanation from a teacher is to help you understand the concept. Generally once you understand it once, you don't need to understand it again - unless you forget, and that's where the practice / spaced repetition comes in. That's why I prefer the teaching part to be as efficient as possible, so I can focus my limited time on the parts that will make me internalise it.