Spring — the product most people still search as Teespring — is a creator print-on-demand marketplace. You bring a design, put it on apparel, and sell through campaign pages and shops. For a long time that was the default “I have a following, I want a tee drop” path: upload art, pick a garment, share a link, they print after the order.
That model is still useful if you already have artwork and you want a simple sell page without standing up Shopify. Marketplace-style discovery and campaign selling are part of how Spring has always worked. It is not trying to be an in-app AI design studio. It assumes you arrive with a file.
If your strength is an audience and a finished graphic, a classic POD marketplace is a reasonable fit. Campaigns made that model famous: share one link, they print after the order, you never touch a box. MRCH starts one step earlier: help you make the art, then sell it from a store that lives in the same app. You can still share a single link; it just points at your live shop instead of a marketplace campaign.