It's for SQL query optimization, not OLAP or similar, so it seems to me like the target audience probably already knows about the psql cli.
I do use command line clients, because I feel they are more available and convenient than GUI tools, but I'm not a PostgreSQL optimization wizard so I could be in the target audience. My customers probably are.
It's easier to tell someone to copy paste a query into Slack to get their weekly insights than teaching them how to set up pgcli or some other gui app. You'd also have to create tightly scoped permissions for everyone who only needs it from time to time.
I'd probably set up something like https://github.com/getredash/redash for these cases though, it's also very user friendly.