after 1M - (2NT) :

• 3♣ shows hearts, 3♦ shows spades, 3♥ hearts, 3♠ spades
• first two bids shows a better hand than direct 3♥/3♠
• when it’s fit, one bid is competitive fit, the other INV+
• when it’s new suit, one is competitive, the other is (near?) GF

direct double shows desire to penalty. pass then double is takeout.