I took a look at this before I undertook building SQL explorer, but it looked like overkill and I didn't want to learn a new query language and introduce a learning curve to every employee who might write queries. But it does look fairly full featured. Have you used it? Is it low-friction enough that people want to use it?
Adoption was good especially for simple queries, people were less focused on the language, and more focused on exploring/modifying examples.
For people who are already familiar with SQL and as you said, less interested in the query language, it may be almost immediately frustrating.
I can absolutely see circumstances where it would be overkill, I have never tried to use it as a performance critical tool, just as more an easy thing to slap on to ease access, two aspects that I have found useful on more than one occasion:
1. HTRAF toolkit is convenient for very basic visualization (depending upon the audience this can be very useful to have at hand quickly)
2. multiple output formats (json in particular) has been helpful in terms of quickly hacking together prototypes in the past