So you have two types of emergency kits.
The minimalist one which is the run out of the house quickly kit is a daysack, it is water (your greatest need usually) some food, a Powercore, a charger, you’d need to last hours until emergency accomodation is found so possibly a basic shelter (tarp, to shade or insulation)
The non-minimalist one you’d potentially keep in the car for when you flee in a more controlled way, not running out a building, there you’d have lot, and of course the car, so more water, more clothing. Some people put this larger one in a metal box in the garden so if they flee an earthquake they don’t re-enter the building but go around outside and collect items from their larger kit.
The issue with this small solar panel is it’s not far off useless, it’s adds about 50% more volume / weight but you can’t be assured of sunshine and it takes days to make 50% recharged. No, you’d want either a 21W solar panel, which is actually very useful and I’d consider in a non-minimalist kit, and/or just plenty / large Powercore.
The greatest need is water, followed by shelter, followed by food, then gadgets and a simple gadget is just a big Powercore. Emergency shelters you’d probably get within 24 hours so that’s how much power you should store, which for most people is about 10Ah per person to keep a phone going.
I own one Anker 21W and two Choetech 19W panels. The Choetech has a better pouch, in my emergency kit in the pouch is a 10Ah Powercore. These solar panels give off 10W typically, so the 40Wh Powercore is fully recharged in about 6 hours of sunshine typically.