I'm more of a believer of "Looks At First Sight". Often whenever it's love at first sight, it's usually based on psychical appearance or such similar factors. Unless you have actual good chemstrity and talked to each other muiltplite times and you are starting to warm up to the person (or people) and it's actual true love and you realize this crush, then I would think of it as "true" love at first sight. If it's a fictional character you're in love with, then I hope you have a reason other than their looks such as having anything in common with them.
Often many girls and guys, guys especially from what I seen though being a girl, tend to look more for the attractive and beautiful or hot and awesome looking person. Many teenagers seem to look more for the looks rather than more the actual personality and behavior or anything in common with people. And if a person falls in love instantly with someone "at first sight" and they never met before, chances are highly likely it's based on the looks alone.
But if you actually have actual chemstrity and it's really true love and you realize you have a crush other than the looks factor, then I say it's safe to call it a actual love at first sight. But that's just my opinion and thoughts.
Lust is a extreme thirst for sex. Looks don't always have to do with sexual desires. Like I understand and quite agree with what you said, but not all people who love someone based on looks wants to have sexual attraction. Like if you're a asexual like me for example. I never really liked someone (well a real person anyways) really but if I did for their looks (which I doubt I ever would) I wouldn't want sex with them because I'm asexual so sex is a big "no-no" for me (love is a big no for me in general.)
So yeah, you are right: if you believe you truly love someone based on only looks alone you might as well end up with your heart shattered. But loving someone for looks only doesn't always really mean they want to have sex with them and/or it doesn't mean they are lusting for them. Like if they're asexual or demisexual even. (Meaning they rarely feel sexually attracted.)
The way you describe your "lust at first sight" sounds more like a "looks at first sight"
Once again I agree with you, but I believe a lust at first sight would be better described as someone who gets sexually attracted easily at first sight and if you want to have sex with them right away. And lust is usually obsessive. It's possible to lust over someone right away and grow obsessed over the looks, but that doesn't always happen. And if a person believes that they're in love for the looks alone and believes they're experiencing love at first sight, they may not even think of sex at all or may not even be thinking of sex right now right away and eventually later they could grow sexual desires later on and not at first.
Loving someone just for their looks or unspoken chemstrity I think should be called Looks at First Sight. Once again, you are right. I just think "lust" isn't the right word and if a person wants to have sex with that person they may not be obsessed at the idea or at first so it's isn't really lust or lust yet. So all in all the way you describe it I think "lust" is the right word.
Good old Doug like always. I quite agree exactly with what the good old Critic says here.