Just like Big Commerce, Shopify is a hosted or cloud e-commerce software, also known as Software as a Service (SaaS).
That means that the e-commerce provider, in this case, Shopify, host and maintain the e-commerce software for you. In return, you don’t need any traditional website hosting since it is all, i.e. hosting and software, delivered as one.
Generally, the benefits of this approach are:
The downsides are usually considered to be the lack of access to the e-commerce software code, meaning it could be difficult customize and integrate (other systems) with. In reality, SaaS providers address this objection by providing apps marketplace and an open API. These allow for extended functionality and the access needed to integrate any system.
It is wrong to compare the higher monthly SaaS subscription cost you have, to a monthly “traditional” website hosting cost, since you get both hosting and software (and maintenance) included with SaaS. In fact, on balance, SaaS is considered as a lower cost of ownership since there is no need to pay an additional cost to keep the software updated.