I have actually used it to rent VPS, buy game keys(mostly steam), donate to some OSS devs who were promoting crypto currency, donated some to random friends(all of whom lost interest or their wallet secrets), converted to other currencies, lost my own wallet key etc.

All these happened in very early days of bitcoin when one could mine using CPU and join a mining pool and others like litecoin were up and coming.

But then, I lost interest as txn fees were eye watering and I was scammed several times by various steam key selling sites never completing my order and blocking me immediately if I complained. I realized that, this non-reversible form of currency was excellent for scam and fraud and I could not cry on the phone about these scams unlike how I can for my MasterCard/Visa/Amex.

Now I come to think of it, if I held onto my bitcoins, I would be retiring wealthy, but alas, I was young and naïve :’)