Playing an instrument is cool but it is not cool if you are uncomfortable with your seat. To play a piano better, one must also have have good and comfortable piano stool or bench to sit on. Some stools are cushioned and some are not, but whichever way, as long it will not disturb one's performance, I guess that would be fine.
There are many top seller stools and benches sold online right now and you can browse on it if you are looking for a good one with a good price. Check it out while they are still available!