There isn't a definitive answer to this question since it largely depends on personal preference. Some people find that 1x11 provides an optimal balance of simplicity and gear range for mountain biking, while others prefer the added versatility of 2x or 3x setups. Ultimately, it's up to the individual rider to decide what works best for them.
That being said, there are some general things to keep in mind when determining whether 1x11 is a good option for mountain biking. One key consideration is the type of terrain you'll be riding on - if you frequently encounter steep climbs or technical trails, a wider gear range may be beneficial. Another thing to think about is how often you plan on shifting gears; if you like to stay in one gear for extended periods of time, a 1x11 setup could be ideal.
Ultimately, there is no right or wrong answer when it comes to choosing between 1x11 and other drivetrain options for mountain biking. It's all about finding what works best for you and your riding style.