That's true, Ste11aeres. Self-esteem, self-efficacy & self-confidence are different traits that can be tough to gauge. Self-efficacy tends to be domain-specific for instance, someone may be really great at fixing cars, or oil painting or soccer. They may be expert to genius even in a given field but have VERY low self-esteem. That can lead to very self-destructive behaviours & bouts of depression. Some people have no skills, have no real self-esteem but mask it behind brash & dashing self-confidence. They talk a great BS line & may talk & flatter themselves into important jobs & privileged positions-until one day someone checks them out more carefully & discovers that they are a bungling, incompetent poser. Some of these people may be psychopathic or sociopathic. Then, there are Narcissistic people. Some of them may have high self-efficacy in a number of fields, many are very smart BUT their self-esteem is extremely fragile, they cannot take even the slightest criticism & can be impossible to be around.
I think, too, that maybe some people with truly low self-esteem have been overly criticized from their childhood & made to feel like they cannot do anything right. This person may just give up on himself & be nervous about doing anything since they fear screwing it all up. As a teacher, I've had students like this & it is terribly sad. Many of these kids actually have high self-efficacy in a given area (math, writing...) BUT they cannot appreciate the quality of their own good work because some idiotic parent (who often thinks s/he is helping the kid improve) finds fault with all their school/homework. I can point out, very specifically, what they've done well BUT they start picking at the work finding flaws that are not even flaws!
As an older Aspie, I think there may be an advantage in that I have had a long time to assess my abilities based on RESULTS in real life & not what someone (either a flatterer or a critic) says. I know, in terms of self-efficacy, that I am a mediocre cook for food but a decent baker. I suck at dancing: I just do. I am very well organized & punctual, very logical & efficient. As far as self-esteem goes, mine is decent, BUT I did not grow up with abusive or dysfunctional parents: mine were very much like 1950s sitcom parents where mom had definite mommy roles & dad did the classic dad stuff.
It also helps to have a 'conventionally decent' appearance. Those standards vary depending upon the cultural context a person lives in. In many places, a person who is considered to be too fat here (& many face flak & have self-esteem issues related to weight) would be considered perfect & even gorgeous somewhere else. The same is true about many traits. Here, a 'normal' person is expected to be quite well educated. In some places, especially for women, you are values more for being fertile & a good home-maker so in such a cultural setting, a heavy-set woman with 5 kids & little education might have no self-esteem issues whatsoever! So much depends, unfortunately, on the messages a person receives from their family, their culture & society in general!