""Apart from appearance, I am concerned that leggings encourage denial of weight gain, especially where it gets to the level of being potentially health threatening.""
I find that the more comfortable I am, the more I walk etc.
I wear leggings and sketchers. I'm out a lot with my Grandchildren and toddlers in the family. That involves on and off buses, sometimes having to fold prams with shopping. I get a day travel pass, but if I can, I'll miss a bus out and walk it. I don't do that in proper clothes and even my Timberland/Uggs.
I'm very active. I see Mums going to soft play and parks in clothes they can barely move in, heels/tight jeans and it puzzles me tbh.
Leggings and long tops means that I can move easily, they wash and i'm not showing anything when I'm bending/getting up and down. I do my hair and wear make-up, but my clothes are practical.
I used to be dog walking and taking relatives out in wheelchairs, being post menopause, I'm too hot and restricted in jeans. I wear the much maligned (on here) Maxi dresses over summer.
Jeans look crap because I struggle to get them to fit.
As for appearance, if you honestly looked at Women in jeans, they don't look any better.
But then neither do the equivalent Men. I've been out with my Grandchildren and like the Mums, there have been Dads who don't want to get dirty/creased/wear appropriate clothing and it's ridiculous.
You are lucky if you fit well fitting cloths that are practical and in your budget. I spend on my face, I get radiotherapy/micro-needling and peels. Watch what I eat. I notice people's skin etc more than their clothes.