To be fair to LookML, it does some great things (kind of like SASS vs CSS). It's great defining constraints in a single variable and then being able to reuse those constraints in any query. It's also wonderful being able to set both default and global constraints: the first can be overwritten, but the second can't.

I was once part of a project where we had certain users and payments we would flag as invalid (for fraud or other reasons). We wanted those records in our data warehouse for very specific reports, but never wanted anyone who was consuming reports to be able to include them in final counts. A global constraint in the LookML definition was a perfect answer. I could still run specific reports directly against Redshift, but there was no concern that a less technical manager would get confused.

I'm not associated with Looker in any way, but have really enjoyed working with their product. I was really hoping they'd stay on the path of independence and IPO, but I can't fault them for taking billions of dollars and calling it a day...