While there is no limitation on the number of sites you can use a single Snipcart account on, all these sites will share the same settings. That includes business branding, address, email templates, shipping/taxes configuration, payment gateways and more.
Orders will also be aggregated together, meaning that it won’t be possible to get orders from a specific store.
If that can work with your online business model, then you are good to go! Just make sure you whitelist all your domains in this section of the dashboard and use absolute URLs when defining data-item-url on your products so that order validation works properly.