I see that the first is pointing to the name Bitcoin and the second is about the digital currency.
To the second example, it is particularly about the spendable coin, fractions , example 0.002btc
Bitcoin is the technology or the blockchain. When you talk about coins on the Bitcoin blockchain, you use bitcoin.
The thing is, they don't appear red in my Grammarly when I tried to post both words it seems like both of them are correct
Both of them are grammatically correct, so your Grammarly app wouldn't be able to mark either of the two as a mistake. It's just the meaning that is different.
You can use both options. Can anyone forbid you to do this?
Is that what you understood from this thread? That there is a law, or that I am proposing there should be one? Bloody hell.