For me, the substitutes helped me getting started with vegan foods, since i was able to still make familiar dishes. That gave me the confidence to try more and more things which are fully vegan to begin with. It's hard to change your diet instantly to completely different foods in one swoop, and it hightens the chance that you shock your guts and feel bad doing it. Which gets people to bounce off a vegan diet. So they are great for that. But even when I mostly eat self cooked stuff today, sometimes I still buy me a pair of beyond patties or something like that.
So they definitely have a place, especially for people who change their diet later in life. I also have a friend who lived vegetarian and later vegan their whole life. And they doesn't like the substitutes that much.