Wow... i severely understmated Ouhi's capacties, i mean... i knew she was much stronger than she acts up, and that strenght was kinda nerfed by her own mental weaknesses, but clearly... she didnt became the leader only because of being a good teacher.
But if this follows the concepts of "restriction and reward" and "biding vows", this Soul Shrine doesn't really have any true offensive or even defensive capacity, I think... she is using it to link everyone's minds, and maybe... cause dilation of time perception to try and exhaust the energy reserves of the minor curses.
Barrier having limited time "manipulation" effects depending on the restrictions imposed by the caster is pretty common, using JJK as an example... there is a character that has a Domain Expansion, but it has no offensive or even defensive ability, it doesn't even forcefully enclose people, someone has to accept the invitation to be entraped, but inside it, time flows differently.
I won't say what the theme of the domain is for those that haven't read it yet, but it is a pretty funny domain, quite harmless too, but it had a big impact in a certain character.
But now... I am scared of one thing... that maybe the one that kills Ouhi is... Sunao... oh man, i hope not, ignoring for a moment if Sunao can recover from whatever fuckery the shithead that kidnapped her is doing to her, she would be devastated if she is the one to do it.