Bitcoin is not only a vessel to store value but it's also really useful in the remittance industry. I can send 100,000$ paying a mere 4$ in fees with Bitcoin while it would cost me 3000$ with PayPal and I'd take some risk to do the paypal transaction while doing the same thing from a traditional bank would cost some money,time & would probably raise questions.
You have a good point regarding small fees relative to large transactions but in case of small transaction fee is a problem.
And yes, big sums via bank transfers and PayPal transfers is problematic.
Everything is beautiful till the point when government starts to ask for information from trade platforms.
https://www.theverge.com/2017/11/29/16717416/us-coinbase-irs-records