Common mallow is a wonderful weed: every part of it is edible and tasty. It also behaves well in a polyculture and is pleasant to be near (no thorns or burrs or anything else bad). I particularly love eating the flowers, which taste the same as the rest of the plant, except with a sweet aftertaste. I am letting it grow everywhere in my garden.
Not only is it a great food, it’s also a spectacular medicinal: soak a bit of it in water for a few hours (or days, or weeks, whatever), and then use that as excellent lotion, conditioner, and valuable ointment for speeding up healing of basically any skin problems I’ve tried so far – sunburns, bruises, wasp stings, scratches, rashes, etc. I’m pretty sure I will never need to buy conditioner, lotion, or aloe vera gel ever again, because mallow water works just as well, and it’s super easy to grow, and it’s a very pleasant volunteer to have everywhere in my garden. 
Other mallows will probably work just as well for the same purpose – I’ve used hollyhock water the same way, and it’s just as great. (Hollyhocks are just as edible and just as drought tolerant and just as happy to volunteer for me, by the way.)
Making mallow water is easy: just stick some bits of the plant into a cup with some water and let it soak for a few hours, and you’ve got mallow water. If you want it stronger, leave it longer. No boiling or anything required. I usually pull off a few dozen leaves, including the long petioles (stems of the leaves), eat the leaves, and put those petioles into some water to soak. The petioles taste good too, but they’re more fibrous and therefore a little harder to chew, so it makes sense to use those for the mallow water. Any part of the plant will work equally well.
I’ve taken to just sticking mallow into water in a tupperware, putting the lid on, and keeping it in the shower to use as conditioner. I grab it out of the shower to use it as lotion or skin ointment whenever I want to. If you want to make it even more effective, you can drop a bit of honey and/or sugar into the water, but the mallow water is already good on its own.
I found out that common mallow has been considered one of the most important medicinal plants for a very long time, because it can be used so easily for those purposes, so I decided to try it, and hey, it works great! Mallow water used to be what people used for sunburn cream, conditioner, and lotion all the time.
I dunno if the lotion and sunburn cream industry has investigated mallow. Probably not; they probably aren’t interested. “Aloe vera” is a keyword that sells products; “common mallow” is less well known for that purpose, so it wouldn’t.
The thing is, my suspicion is that common mallow isn’t particularly special, and neither is aloe vera – the key is probably mucilage, and they’re both high in mucilage. I suspect that if I stuck some Siberian elm bark into water, it would probably work similarly. (Slippery elm bark is known to be good for sore throats, and that turns out to be because it is – you guessed it! – high in mucilage. And Siberian elm is in the same genus and can be used in the same ways.)
So you could try something similar with basically any convenient edible plant that is high in mucilage. Probably you’d want to stick with edible plants because your skin is an organ that absorbs chemicals just as effectively as your digestive system – that’s why you can test for food allergies by rubbing a bit of the food on your skin and leaving the residue there for awhile. If you use an edible plant, it will be safe for your skin.
I think every member of the mallow family is high in mucilage, and I’m pretty sure every member of the mallow family (except cotton) is edible, and it’s a huge plant family with a vast number of species. So you could probably experiment with any convenient member of the mallow family (except cotton) for this purpose.
My suspicion is that common mallow was prized for this purpose because it’s so easy to find, and that made it convenient. If you have some other mallow that is more convenient (such as a linden tree), I suspect that you could use that just as effectively instead.
Anyway, just some thoughts about common mallow!
Anything delicious and pleasant to walk near (no burrs, spines, thorns, etc.) that can grow in unwatered dry spaces belongs in my garden! 