I tried this method, but my piano teacher said it was not very good, because the piano would rebound when it touched the keyboard. But the table won't, so playing more on the table will make your fingers think that the strength is like this, and the muscles on your fingers will remember it. When you play the real piano again, you will feel stuck on the keys. That's because your muscles think you have to work harder and use the power of the piano on the table, so the sound will become very long.

In addition, the fingers have reflex nerves. If you play a piece of music well, your fingers will remember this fingering. Even if you play it again after ten years, you will be very skilled after practice! Pianists are like this. When they learn music, they try to make their fingers remember it by themselves without using their brains, because muscle memory is much more effective than brain memory.

Having said that, in short, you should make full use of the time you can touch the piano and let your fingers write it down. However, you should practice hard!