When I was collecting Bryce Harper, I bought stacks of these patches and relics. I'm no longer collecting much of anything and have been selling off much of my collection. The relics still bring more $ than regular cards, even some graded cards, but I'm not getting anywhere close to what I paid.
In general I'm against cutting up jerseys or shaving bats just to make a card. I understand the concept behind it, but I think it's a shame to cut up game used materials. I have less heartburn about cutting up modern day players than I do seeing vintage HOF player's uniforms or bats being hacked up for a card; that in itself should be a crime.