1) Alternate Sighting Solution
If my RDS goes down / optic is damaged so that I can't use it as a ghost ring for effective hits my VIS Laser is an alternative sighting solution. This is why so prefer Green VIS Lasers for their superior visibility compared to red. That being said - on bright sunny days the effective range of the VIS Laser is likely not going to reach too far.
It is also viable for when you cannot obtain a proper cheekweld while getting on the optic, such as asymmetric shooting positions and wearing a protective mask.
2) Signaling
VIS Lasers offer a unique advantage in signaling. Ordering a teammate to cover a door or window is often made more effective by lasing said door or window.
It can also be used in link-up / consolidation procedures (lasing under a closed door with with part of the force composition behind it for example) as part of a PACE Plan if Chemlights are unavailable. This needs to be briefed and agreed upon and used only under specific situations if adopted - lasing teammates is unacceptable and could lead to blue on blue incidents.
3) Tracking
Using a VIS Laser to track a moving target can work, and is sometimes easier to provide shot correction and increasing a lead as needed. Further, having teammates see the VIS Laser tracking alongside cover can help them determine exactly when to open up when there is a break in said cover (window, mud hikes, breaks in a wall).
Green VIS Laser can also help aid human tracking by registering footprints, blood spoor when white light spill is undesired.
4) Deescalation
OCONUS - charging a weapon system will often obtain more effect than simply pointing a weapon at folks. A VIS Laser (or several) can often deescalate situations. I had my best luck at this by lasing Fighting Aged Guys groins.
5) IED Tripwire Detection: I'm alive and have all my limbs because of this. A VIS Laser emits a straight beam that, when encountering a tripwire, will refract off it.
For this TTP to be effective, a fighting formation set with one PAX lasing and one PAX observing (either one can call a halt) with lethal cover in place and part of the fighting formation. It's a niche solution, but sometimes a necessary one. Same
Principle applies to NODS.
It's slow, but far preferable to CASEVAC'ing a wounded teammate.
For those reason, an IR/VIS Laser can typically be found in every weapons platform I use.