> Is buddihsm real? Does it have any basis in scientific and objective reality? Or is it fiction?

These are Buddhist questions. :)

The Buddha famously told his followers not to accept his teaching merely because he said it, instead he told them to "go and see for yourself." The point is that if you want to know if buddhism is real, try out the practices and see if they make sense to you and make a difference. If the practices work, adopt them, if you find them worthless, abandon them.

You get free will and karma in Buddhism. Great 2-for-1 special.

Another way to come at it is to consider the good old Four Noble Truths. There are different ways to say them but this is how I learned them:

* Life is full of suffering

* Suffering is caused by attachment to desire

* There is a way beyond attachment

* Meditation and Buddhism is the way beyond attachment (or to Enlightenment, if you prefer)

> If it is fiction, why is it so popular among technical people like people who come to HN? Are the people on HN who are interested in Buddhism aware it is fiction/real?

Because it sounds cool and intellectual.

This is the same reason crypto-buddhist "philosophies" became popular in the Hindu-sphere post the decline of Ancient Vedic religion, which had no concept of rebirth and rather focused on Rta (cosmic / natural order), vrata (duty), kratu (will) etc...

Looking enlightened is more important than actually being enlightened.

Well, if you come at it from the mindfulness angle, there are real studies showing that mindfulness works. https://pmc.ncbi.nlm.nih.gov/articles/PMC8083197/ and similarly, if you come at it from the religious angle, you can trace a lot of the aspects of mindfulness back to the Buddha's original teachings as recorded in canon. And if you ask if there is a fundamental point beyond those, I think the answer is that there is none recorded - the best description I have been able to get of Nirvana is that it is a state of perfect mindfulness.

Like other religions, buddhism can help reach a better state of mind. But there is no proof for the idea of repeated rebirths and karma.

This is a strange question. It's like asking if Christianity has any basis in scientific and objective reality, which as a religion it does not, none do. It doesn't even make any sense to ask the question, like what does an objective reality of a religion even mean? You explicitly disclaimed discussion about the cognitive benefits of its practice so I'm not really sure what else you could be asking concretely.