Streaming video veteran Netflix (NASDAQ:NFLX) is crushing the market in 2020. The stock has gained 30% year-to-date while the S&P 500 market index fell 5% over the same period. Netflix is one of the biggest winners in the COVID-19 crisis, adding millions of new subscribers as stay-at-home orders left consumers hungry for new entertainment options.

The health crisis has most certainly accelerated Netflix's long-term growth ambitions and investors who buy the stock today will pocket impressive returns in the long run. But I don't see this stock as a no-brainer buy for every investor right now.

A red Netflix logo in the form of a sign on a beige stucco wall.

Image source: Netflix.

Are you serious?

Feel free to gasp, swoon, ask for the smelling salts, and so on. Netflix is the biggest winner in my own real-money investing portfolio by far and you'll often find me pounding the table regarding the many reasons why you should buy the stock. So why isn't it a total no-brainer buy today?

The company is growing up and market makers are finally treating it as a mature market leader. Patient investors can still find lots of value here over the long haul but the market-stomping returns of the last five months won't continue.

How Netflix beat the market year-to-date

If you bought Netflix in January, when I told you that the timing was right, you'd have a 21% return on that investment so far. Meanwhile, the broader market fell 8%. Mr. Market worried about all the wrong things in the company's fourth-quarter report, which set the stock up for a quick rise in the spring.

The coronavirus pandemic helped the company deliver exciting growth in the first quarter, and the addition of 2.3 million North American subscribers showed that Netflix still has room to grow in this crucial market. The larger growth opportunity still lies abroad. The 3.4% quarter-over-quarter subscriber increase in North America was dwarfed by the company's other three geographic divisions. Netflix saw 9% growth in Latin American subscribers, 13% more accounts in Europe, Middle East, and Africa, and the Asia-Pacific market led the pack with a 22% jump.

Netflix also proved that it can generate positive cash flows under some circumstances, such as a sudden stop to original content productions in the first quarter. The company will soon fall back to negative free cash flows again, only to climb back up to the positive side over the next couple of years. This time, the cash generation will be powered by sustainable long-term improvements rather than a sudden and unpredictable health crisis. A few years from now, traditional value hounds will be able to calculate Netflix's true market value based on growing and predictably positive cash flows.

Photo from the back of a man scratching his head.

Image source: Getty Images.

So why isn't this a no-brainer buy?

If you think I just told you to buy Netflix, even within spitting distance of the stock's all-time highs, you're not wrong -- but this still isn't a stock for every portfolio anymore.

The road ahead will be bumpy while Netflix works toward that long-term ambition of organic cash flow growth. Until then, the stock may be prone to sharp jumps and plunges along the way. In the past, I would usually have recommended buying the stock anyway because the long-term returns promised to be large enough to make up for short-term pains.

That's changing in a hurry. These days, I recommend that you keep an eye on Netflix and get ready to buy on the dips -- and I'm sure we'll see plenty of those before the company turns into a sustainable cash machine.

In short, Netflix's stock is fairly valued right now. Feel free to pick up a few shares if you're looking for a long-term value play, but growth investors can find better ideas elsewhere.