I would have replied earlier but had to get my account started here lol. But Big Mom is actually my favorite character in all of One Piece, and I have many friends who love her as well (not to the extent I do) so I figure I can essentially tell you why many are enamoured with her. I cannot be as brief but I'll try. Hopefully this is entertaining and maybe thought-provoking. So basically for me I originally liked Boa mostly because she was a straight-edged strong woman. To this day she is 10 toes down no matter who is in front of her and will inflict tremendous casualties no matter the result. In comes Big Mom. She is a fever dream of a character, she completely blew my mind. For starters the moment Luffy landed on her island he was located immediately. THE FUCKING TREES WERE WATCHING HIM, and while he was travelling through her territory the fauna were insulting him throughout the forest. Never in my life would I have imagined such a thing. There are major implications for this but I'm brief and will stick to canon. But regardless this adds to her tactical prowess. She definitely underestimated Luffy but realized how much of a threat he was and decided to chase him. But that has been the hubris which carries Luffy to greatness. Lin Lin has an actual thunderstorm on her left shoulder that insults you. An actual flaming sun on her right shoulder that also insults you. And lastly a sword that as you guessed it insults you. All of them can move freely as well. To me you cannot fight Big Mom on the ones- you get jumped regardless because of them. You should not be able to sneak her- which is kinda wack that you can lol. I could go on but I believe this is enough. I love her abilities, I love her VA and design especially in the latest episodes. She can fight anyone in the series and no one would be able say she loses a fight easily. Hell she took this L by technicality of ring out lol! They didn't have enough strength to get a KO so they pushed her out of the ring lol. Jokes aside I hope this helps.