I'm saying this in terms of the fact that Inner Sect disciples' gets challenges not just based on combat alone. Secondary/tertiary skills or not, the fact is that they have to invest on it just as much as we do ours. Besides, if combat stealth is totally applicable. It's like throwing a smoke bomb or a flash bang in the middle of the fight then disappearing. Couple that with the fact that we now have Zhengui, Sixiang, and Hanyi to distract our opponents.
Let's use Ji Rong as an example. Right now, I'm pretty confident that Ji Rong can't beat us, but that's because of our spirits and our group support arts(which is essentially where our music build comes in). On our own? Yeah, good luck. In my eyes, Ji Rong is spec in Speed (yes, I'm using that term instead of Instant Movement, bite me) and Perception. Can they be applicable to combat? Hell yeah of course! Then what makes Stealth any less of an option as a combat even though it's totally valid. Heck, right now Ji Rong is starting to move away a little from his path to be a super puncher in order to learn more about Government. Same goes for us, and CRX is totally all for that as well in the side.
If your problem is how I'm graphing the build, I admit it ain't perfect, not accurate maybe even. Yet, it's also ideal for us to move towards that. I'm speaking not just of our Moon patrons synergy, but also the role CRX seems to plan for us. In other words, it's for the far future rather than this current quest where we have to worry for combat (though I'd argue it'd still work)