A few of many reasons: because it is the hardest to create, has an actual limit to its supply, and there's no ceo that can just change its parameters or functionality.
Discussion
what?
hardest to create?
aren't the supply of both bitcoin and monero known?
or do you mean energy investment in mining?
also
monero has no CEO....
and also also
a hard cap is another tradeoff that nobody is sure will work out. there are good reasons to have tail emission.