India lost the second T20I by four wickets in the last over.
Last month, India had also lost the 50-over series as a result of a last-ball defeat in the second ODI in Mackay.
"If you look at the way Tahlia McGrath batted today, we can see the confidence they are getting from a tournament like WBBL. They are ready to play international cricket," Kaur said in the post-match presser.
"She has not played much in international cricket but got to play many matches before playing for Australia. We do have a few young players who haven't played much cricket at the highest level like (pacer) Renuka Singh.
"She has done really well in the domestic cricket but still doesn't have that much experience. If we had women's IPL, the domestic players would get a lot of chances to prove themselves under pressure."
Chasing 119 to win, Australia were 96/6 after 17 overs but Shikha Pandey conceded 11 runs in the 18th over while Renuka Singh gave away 13 in the penultimate over, which titled the game in the home team’s favour.
Harmanpreet cited the example of men's IPL where youngsters get to play with top players of world cricket.
"Even when we see a young talent play, we can see the maturity in their game. They would have played at least 40-50 IPL games by then.
"I think that is the only reason we are lagging right now. Before getting to play in international, if we get a chance to play in a domestic tournament like IPL, we will definitely improve.
"In Australia, they get 20-30 matches in WBBL before getting to international cricket. It will develop your skills and give you experience so that you don't feel lost in international cricket," she said.
(With PTI inputs)