These work ok, but there are a couple issues:

• A large batch requires a lot of muffin tins
• Cleaning muffin tins is annoying
• It can be hard to get them out of the tins

I've switched to a different system where I freeze a flat tray in a thin enough layer that I can break it easily:

It takes a bit of practice getting the layer thickness right: generally the higher the water content the thinner it needs to be if you don't want an awkward block.

I put a layer in a freezer bag:

Before putting in additional layers I put down a scrap of parchment paper or wax paper:

It's easier and faster than the puck method, though with higher risk of accidentally ending up with a block and needing to defrost some.