Check the mod priority guide:
https://docs.google.com/spreadsheets/d/1ty239kyJbBs1sLhTo1JvSWuN0mIJsK1nwVdI6OLLtXo/view?rm=minimalC96 is a Flare HG, which used to be completely and utterly useless. Due to the changes to Flares now offering Night Vision instead, C96 now suddenly has a niche long after her MOD was released.
MOD1 improves C96’s Skill 1 to give 90% Night Vision, returning all dolls to almost daytime Accuracy. Her new Skill 2,
Night Sky Pursuer, grants allies 2 ammo to their current clip (if they even have a clip size) and raises their Critical Damage by 20%. She also gets the usual array of buffs, like stat upgrades and improved tiles.
You may feel like C96 is forced into Position 5 if you're using her as an HG in RF teams at night, thanks to her odd tile layout, but her tiles only offer Accuracy so they can often be safely ignored. The 20% Critical Damage bonus may as well be an effective 20% DPS increase for RFs with their natural nearly-capped Crit Rate, while the huge amounts of Accuracy she effectively gives can really help RFs a lot against evasive enemies. With how SCAR-L’s additive damage benefits greatly from having a high Critical Rate, C96 is a decent option for allowing SCAR-L to wear a VFL at night.
Note that you would never want C96 with MGs, because Nova does exactly this except way WAY better (she gives a flat 80 Accuracy to MGs at night, C96 does not even come close).
There’s nothing particularly remarkable about C96, but all in all, what she gains does make her a fairly decent HG to pair with RFs for night battles particularly against more evasive enemies.
MOD1 alone is cheap and offers pretty much all of this new support capabilities for her. MOD2 is nice as well for the Crit Damage buff but also not strictly necessary. Her Special Equipment just offers herself some Crit Rate and Evasion; don’t bother and use a S.F. Modified Tactical Light instead.