A product catalogue versus a distribution gig
Print on demand is a light retail model: you upload designs, a supplier prints and ships each item as it is ordered, and you keep the margin. There is no inventory risk, but the margin per item is thin and — crucially — a listing only sells if people find it, which usually means marketing or a marketplace's own search traffic.
Clipping has no product and no supplier. You are paid on the reach of the clips you post, not on a per-unit margin after a sale.
Where print on demand genuinely wins
If you have design ability, print on demand can build a catalogue that sells with little ongoing work once a design catches on, and marketplace search can bring buyers you did not pay for. It creates listings that are an asset of sorts, and a hit design can sell for a long time.
The reality is that most designs sell little without promotion, and the per-sale margin is small, so volume matters. Clipping's earnings depend on the views your clips receive, but it needs neither design skill nor a marketing budget to begin.