Not sure what all the hubbub about armor/helmets is. Here's how I see this:
1. We're not in the kinetic phase of Civil War 2 yet, so no walking around in helmet and body armor as you'll just scare the sheep and get swatted
2. If you're concerned about being shot in the current environment where overt armor is a no-no, there are concealed/hidden/civilian anti-ballistic clothing/armor you can wear that won't get you swatted.
3. If you're considering body armor for #1 above, a plate carrier and Level IV plates to stop multiple rifle rounds to center mass is the way to go. Start training now hiking/running with a place carrier/plates to adjust to the added weight, especially if you're older and not used to carrying. In my case, I just need to lose 30lb, then I can carry the extra 30lb of weapons/gear/armor no problem. Decide if you want front/rear or just front. My preference is just front to balance weight/mobility with protection. As the dude in Black Hawk Down who got shot in the back and died said, "I'm not planning on getting shot running away". Of course, that didn't work out so well for him in a MOUT/Urban shootout where fire was coming from 360 degrees.
4. A helmet is a good addition to the above. In a stand-up fight, you will be behind cover/prone and a helmet will protect your exposed head. The plate carrier/plates will help when moving tactically/bounding/break contact under fire, but a helmet should be considered an essential part of this kit.
5. More importantly, a helmet will serve as a platform for mounting NVG, tactical light/infrared light, etc. Most combat operations (and many police actions) take place at night due to the advantages US forces have with NVG's. That won't change in any scenario we're talking about here.
6. In my .mil career, I spent time wearing in a soft cover during the day, a watch cap (at night), and in kpot (PASGT kevler helmet) for various activities. The kpot was always available to put on at a moments notice and that's how I would use it. No need to wear it 24/7, just when action was suspected/imminent or there was a need for NVG's.
The post above mentioning artillery and airburst munitions is spot on in a kinetic event. It will be used and it most likely won't be friendly (does it matter if friendly or enemy fire is raining down on your position?)
So, bottom line, if you think you'll need to engage in combat operations during a kinetic event, protective helmet and plate carrier is necessary. If you think you'll be a partisan, always in disguise and blending in, then the above is unnecessary. This is purely academic as of course the US one big, happy Republic and we will not see Civil War 2 in our lifetime. A simple reason for having these things on hand is "airsoft" or paintball, which if you've been out of the military for a while (or never in), is a great way for us older folks or those new to "combat" to train the typical infantry scenarios of assault an objective, clear a building, etc. or just learn/train what a dynamic firefight is like without the risk of death. For many younger folks, it's very different than running and gunning in Call of Duty, which is about the most experience they have.
As an aside, one of the most memorable airsoft/paintball moments I ever had was when my team was engaged with another team, and my assault unit flanked the "enemy" while our base of fire kept them occupied. The squeals from the enemy (my 16yo son included) as we assaulted through the objective and rained fire down on targets at a range of less than 30ft was priceless. (Yes, the paintballs hurt and yes they leave welts when simple clothing is hit. A simple lesson to a bunch of teenagers on the value of squad infantry tactics and pure aggression in combat. The enemy "dead" probably wished they had helmets and body armor given the number of hits they suffered.