Although both items are labeled as 220-grit, the pads are softer with a less aggressive scratch pattern.
With use, a 220-grit pad will soften very quickly to the equivalent of 400-grit sandpaper - making used pads ideal for finish sanding between layers of topcoat or prep sanding an EXISTING finish.
220-grit sandpaper is too aggressive for finish sanding but works well for the final round of prep sanding of open-grained raw wood such as Cherry, Pine, Maple, Birch, or Alder.
Pads are our favorite. The pads last a long time, can be rinsed to remove sanding residue and also have the benefit of being flexible, making corners and edges much easier to sand.