Ok focus here is my 2 cents for piano training. We have seen lots ideal hands positions using finger tips that finger is curved and so as some professional pianist who played with semi flat straight fingers using pad of finger rather tip.
I have done lots trials and experinment and read lots articles so as consulting with top professionals see how they manage to produce a "tone " they wanted.
Playing with finger tip:
This is using more of top 2 joints of finger muslces, so called steel fingers, the aim is to develop top two joints, this approach add very little stress on your palm, so the rest of the fingers after second joints. eg whrist is supple still. This is good for playing Mozart, quick passages.
Playing with semi striaght fingers(flat finer tip)
This is good for relaxing your finger tip when power is required using your second resource, which is playing with your finger pad that you make your finger semi straight, and now you will find you are uisng more muscles from your palm than your finger tips. So the game is you alternate between finger tips and finger pad. to recovery.As matter of fact, you are now resting your finger tip but using finger pad.
Playing with semi stright finger improves your hands dexterity so as power.
This means, people with a bigger palm not necessary a long fingers but skinny in theory should have more reserves in energy.
Guys, go and try you will find this is very useful, and now its up to you to spend time on piano or not. Have a good day.
I hope this makes sense, and helps this community.
John