The company needed to reach a new level, because at first it was just an Instagram store. Therefore, the creation of a large online store is a necessary measure that significantly increases sales volumes.
An online store on Instagram is a good way to start a business, but if you want to scale, you just need a full-fledged online platform to distribute your product further.
The site is another level of business development, especially the product business. An Instagram store can lose a significant percentage of potential customers simply because of limitations in functionality, filtering and product ordering. A full-fledged site can easily fix this.