1. With Shopify you can make an online store by yourself in 3-7 days with nearly no investments ($ 100).
2. Shopify is the best first step to the real online shop. All your efforts on making Shopify store will not be lost when you decide to make a real online store.
3. No third good
1. Forget #1 on Google. Shopify has some SEO features but those are mostly for better sales of Shopify subscriptions and have nothing to do with real needs of SEO.
2. Expensive custom design. You can make any design on Shopify but it will be 5 times more expensive than on WordPress with WooCommerce.
3. Sooner or later you will have to leave Shopify.