Question is, now that some of the biggest players on Wall Street have made it easy to put money into Bitcoin, should you? I would steer clear for the simple reason that cryptocurrencies are speculations without any intrinsic value, or perhaps worse. As the Financial Times columnist Jemima Kelly scathingly wrote, “Crypto is not just a zero-sum game, in which one person only gains if another person loses; its many moral deficiencies make it a negative-sum game.”

The legendary investor Howard Marks recently highlighted a critical distinction about investing that is worth keeping in mind. Marks is co-founder of Oaktree Capital Management, a global investor with $183 billion in assets under management as of Sept. 30. He is a legendary contrarian, attracted to unloved markets, wary of consensus thinking and eager to uncover long-term trends to ride. Contrarians that successfully invest over the long-haul are admired in finance because genuine practitioners are rare. As John Maynard Keynes put it, when it comes to professional money management, “Worldly wisdom teaches that it is better for reputation to fail conventionally than to succeed unconventionally.”

In an interview on Bloomberg’s “Merryn Talks Money” podcast, Marks said the critical divide in the investment world involves cash flow and the lack of it. Investments with intrinsic value generate cash flow. These investments include stocks, bonds and buildings. Investments (really speculations) without intrinsic value don’t produce a stream of cash and these speculations include gold, art, furs, Bitcoin and crypto. People may buy crypto because it’s fun and people have long bought gold from superstition, he says, but these speculations are “only worth what people will pay for it.”

The distinction is worth keeping in mind when reading about the new opportunities opened by the Bitcoin ETFs. For most employees and entrepreneurs saving for their economic security in retirement, their children’s and grandchildren’s education, and building a household financial buffer against turbulent times, they should stick with assets with intrinsic value, like high-quality stocks and bonds. Of course, if someone wants to take a flyer speculating that Bitcoin will rally and they’ll find a bidder at a higher price, there’s nothing wrong with that. But I would recommend taking the money out of your entertainment budget. That way your current and future standard of living isn’t at risk if the bet goes bad.

Chris Farrell is senior economics contributor, “Marketplace”; commentator for Minnesota Public Radio.