I hear you. But a full size pistol with a suppressor is still much smaller and lighter than a small AR. And if you want to shoot subsonic, is arguably a better packaging of a more terminally effective cartridge (vs. 300BLK or something like that). I also don't know how suppressed pistols are usually carried, but likely still much less obtrusive than an AR.
This is pretty common and understandable thinking, until someone spends time doing a lot of shooting and especially training with suppressed pistols and alternatives - evaluating each for its utility for a given job. The thinking ahead and thinking through the various options and scenarios that impact a decision for one tool vs another.
At the core of it all is - what exactly are you selecting a tool and training for? As in, what
specific use-case would you want an "unobtrusive", suppressed gun at all?
Especially where unobtrusive is a superior use or survival requirement over the value of superior terminal effects? Especially when subsonic rifle rounds are usually far more devastating than subsonic pistol, given their heavy-for-caliber and subsonic-specific construction designs, and what happens on impact with them compared to pistol bullets.
Within all this, does unobtrusive include needing the pistol to be suppressed already, or are we talking assembling the two parts only when ready to use?
Also, when would unobtrusive be superior to the shootability and ability to hit more accurately that comes with shoulder-mounted guns?
All this, where sound-suppression
also isn't important enough to warrant subsonic rimfire, which is a lot quieter?
Exactly what scenario do all those requirements come together to argue for the superior choice being a suppressed centerfire pistol?
There are some
exceedingly narrow, specific jobs that may warrant that, none of which are legal or advisable unless covered by Title 50 protections. And even then, in reality, there are vanishingly few, given the broad suite of options available to solve those types of problems.