Cushion and Seat

The issue
The newest snapshot (26.3 snapshot 3) added "cushion" which can be sit on and can be placed on any flat surface (the cushion will adjust its height to be on top of that surface).

This is achieved by cushion being entity - like item frames or armor stands. This on itself is mostly fine. But the issue is when it comes to interaction with redstone - cushion cannot be pushed by pistons or pulled by slime blocks in same fashion as blocks. Which is shame. 

The solution
To solve this, i propose adding new block called "seat" - it will be crafted from cushion and slab, and unlike cushion it will be ordinary slab block. So while it will lose ability to adjust its height (like cushion does), it would gain ability to be properly pushed and pulled around by pistons, slime blocks and honey blocks.

The purpose
The main usage of this "seat" block would be in flying machines - currently if you want to ride flying machine, you can either stand on it or ride minecart/boat - both of which are pretty janky and prone to fall, which can lead to death in some cases (like traversing over void in end). 

With seat block, you can just sit on it and being carried around without any issue.

(it can be used in any redstone, but this would be the strongest use case in my opinion)