Blocks Cushions can be placed on don't make any sense to place on.

The cushion is able to overlap with many blocks but some blocks should make no sense whatsoever to place such as Stonecutters, Enchanting Tables, Amethyst Clusters, etc. as a few of these might either be bad or look unnecessarily painful. Blocks that can have Cushions placed on them should have a #nbt tag on them to indicate they can. Also using cushions on chains or string to create a fast moving system might make Minecarts obsolete for travel. When sitting on a cushion the player should not interact with any other cushion in range as this might break the game too early in a bad way.

Some images and a video link should show these arguments.

https://www.reddit.com/r/Minecraft/comments/1upxul1/new_tech_cushion_line/?solution=cee5f62c44f24f8fcee5f62c44f24f8f&js_challenge=1&token=7afd7253fec22262ff1c52b1703fe9ecc5b2ff402c83c30f01d4bc20af6ee455&jsc_orig_r=&utm_source=embedv2&utm_medium=post_embed&utm_content=post_body&embed_host_url=nullsrcdoc

I'm not saying it's bad at all but should be adjusted as it's still in Snapshot and Preview for now.