When to use te form and past tense

Question

Was going through my Genki book and saw an example sentence of te form verb but it ended in past tense. (言う いってた) Why use the te form at all and not just past tense

「あきらさんは何て言ってた？」
「チョコレートを食べすぎたって言ってた。」

Answer 1

I think which version you use depends here also on the continuity of the action.

Maybe compare:
「...彼は言った。 」
「...彼は言っていた。 」

With:
"He (once?) said..."
"He used to say..." OR "He was saying..."