Why don't people today use the ascendant sign in stead of the sun like they did in ancient times?

in ancient time they used the ascendant sign, it was also over a shorter time period so it gave more specific detail on a persons personality unlike the sun which spands much much longer and everyone that falls in that specific sign are no where near simaliar and some people like me dont relate to their sun sun to much or at all. im a scorpio ascendant and my sun sign is in cancer and i feel more like a scorpio and i act more like one and i definitely think like one and my physical appearance fits that of scorpio not cancer and i guess pluto conjunct my ascendant just intensives it. don't get me wrong i have some traits of cancer but if i took a test or if i didnt tell you would think i was a scorpio so why did they change it form the ascendant to the sun sign especially if everyone relates more to there ascendant then there sun like me. do you think it would be better if they change it back to the ascendant because it does explain why most people dont feel like they can relate to their sun sign because of their ascendant is what they act like and relate to more. plus i was going to get a zodiac tattoo and i don't know if i should get the cancer or the scorpio because the only one they is talked about and people know is the sun but i feel more like the ascendant but if i get the scorpio im afraid people are goin to look at me like im stupid because there going to say im a cancer not scorpio even though im getting the sun(cancer), moon(in pisces) and ascendant(scorpio) sign tattooed on me but the main sign of the three is going to be bigger then the other to and i want to get this clarified before i get it done. plus it also explains a lot when i comes o relationships to why when it says to people suns sign are compatible but they can't stand each other and vise versa it s because the sun doesn't even determine compatibility in that area like venus and mars(which are in leo) so please give me some feedback on everything especially please except for the venus and mars thing that can be save for another question. thanks a lot and please be specific and detailed i would appreciate it lol