Because up until Broadcom bought them, it was a good product with a ton of useful features, endless supported integrations with 3rd party software and hardware, relatively easy to learn/use, with good support, all at reasonable and flexible price points depending on your needs.

Of course Broadcom has now thrown all of that into the toilet...

Because if you throw enough money at them, they'll trip over themselves trying to fix your production critical issue in 4 hours or less, and that's valuable to business because they get to go "it's not our fault the site was down and we lost $2 million, it's our vendor's support team that was inadequate"