I have no interest in the 5.7, so I have no dog in this hunt.
That said - I see that there are JHPs available for the 5.7. I am also a firm believer in firing until the threat ceases. Unless you are using a 40mm grenade launcher and blowing your adversary to pieces (very messy inside the home and hard to tell where the shrapnel will go...) you are going to be firing multiple rounds. With minimal recoil and 50 rounds in the mag, seems like you have the ability to get off quite a few bursts before needing to reload.
Basically, I see this as a higher-capacity sub-gun - no better and no worse but with more ammo in the mag. With AP ammo for military use, it is arguably better than a pistol-caliber sub gun due to the ability to defeat soft body armor - but since that ammo is not available to civilians, it is a moot point.
It is not really a rifle (it is a PDW), so saying that a 5.56 is better is kinda stating the obvious. Also note that not everyone lives in a state where getting a SBR and/or a suppressor is an option.
The bigger issue is deciding to move inside the home, which is the stated reason for wanting a more compact arm. Personally, unless you have no choice, I feel this is a very bad tactic. Much better to hunker down and let the BG(s) come to you - in which case the length of the arm is much less of an issue.
If you have family on the other end of the home - really think hard about relocating them closer to your own bedroom, if at all possible. Even if it means some home remodeling. That's probably money better spent, than spending it on SBRs, tax stamps, suppressors, and the like - only to end up dead because you tried to clear the house by yourself and ended up getting jumped while clearing a corner.
I know, I know - home remodeling isn't as sexy as getting all the cool SWAT toys, but the wife will probably appreciate it more.
As always, JMHO and YMMV. Carry on.