Buying bitcoin as a long term investment is risky. All investments are risky. The long term prospect look very good. Bitcoin has outperformed any currency on the planet. You can buy some and send it to an investment platform and use it to diversify into multiple coins. You can lend it, or you can just sit on it.

I only buy bitcoin with Coinbase. If you use my link to buy $100 or more we both get $10. Most of the currencies I own were purchased with bitcoin I got for Free.