If you look at the origination of the shopify is to help people who want to sell products online that’s the main moto of shopify website where you can create your own website and sell products.
But if you are looking to start blogging then shopify will be not the best option for you because in the cost of building and maintaining a blog on shopify you can easily build a blog on wordpress for a year or more.
And in wordpress there are 1000’s of free plugins & themes that will help and ease your blogging journey but for the same kind of plugins & themes in shopify you need to pay hundreds of dollars.
But here’s the catch that if you want to build a blog page on shopify to promote your products organically via SEO then you can do that but just to start a blog shopify is just not good for you.