Why you should never rely on romanizations when learning Korean Alphabet/Hangeul

All Teenagers are now being addicted to kpop and kdramas, most of them relies on romanization when they study it. But why shouldn't you rely on Romanizations?

This is because Hangeul has some letters that goes between R and L. Some can also have the same sound sometimes.
Also, when one writes his/her name in Hangeul, they base it on the romanization which is wrong. For example, if you write TAYLOR you should look for the romanization that goes TEILOR because when romanizing, koreans depend on the sound not the spelling. So next time you write some names in Hangeul, depend on the sound.