"#Bitcoin    isn't scarce because you can split it into smaller units"

I'm going to break down why this is not true in a way that anyone can understand:

You have 2 whole pizzas that are not cut. Each one is identical in size.

If one pizza is cut into 10 slices while the other is cut into 8, does the one with 10 slices magically have more food?

No.

You have the same amount of pizza, but when you have 8 slices, each slice is 12.5% of a pizza and when you have 10 slices each slice is 10% of a pizza.

Now let's move away from pizzas and talk about Bitcoin.

The Bitcoin network issues a currency - BTC. There will only ever be 21,000,000 of these currency units. 1 BTC will always be 0.0000047619% of the network.

The 21,000,000 is arbitrary - the algorithm used by the network stops producing more coins when there are 21,000,000 in existence. This number could have been 100M, 500B, or 100T. It doesn't matter.

Each BTC can be split into 100,000,000 units called Satoshis. Smaller units means the network can handle smaller transactions.

You can compare BTC and Satoshis to Dollars and Cents. In total, there are 2.1 quadrillion Satoshis. Today you can buy ~1500 Satoshis for 1 USD. You can split $1 into 100 cents.

If I have 10,000 cents, do I have more money than someone who has $100?

No.

Both of us have 10,000 cents or $100. Each one is equal to the other! $100 X 100 cents = 10,000 cents