BTC ATMs are still wildly popular with scammers.

I use my limited holding to buy my VPN subscription, and occasionally bung a few donations to various people. I've never considered BTC an investment.

Yes.

As for international transfers - I never thought it's a good use case. Int'l wire transfers are getting cheaper and faster, so there's a diminishing market of people who want to do it.

For what it's used for - DeFi (i.e. financial instruments of all sorts) is an awesome use case, IMHO way better than the traditional system. The problem is that underlying assets are crap/virtual tokens - if it were actual shares/real world things it would dominate the market. The issue is with SEC/regulations - super hard to make a security tradeable on blockchain. Before SEC got involved (in 2012?) the majority of trading was on actual companies that paid off dividends, like the first ASIC projects, satoshi dice and so on.