It’s stylistic. Sympathetic magick is “low magick”, traditional witchcraft where you are only relying on yourself, and your link to the target. The candle is representing your love, hence the ‘sympathy’ part.
Here’s a link about sympathetic magick.
Other examples are poppets/voodoo dolls, and witches ladders. It’s a very practical and more independent approach, and more freeform and open to personal adjustment. You can literally stand out in the woods/kitchen/bar, grab whatever is to hand and make it up as you go along.
Conversely, ‘high magick’ is your ceremonial, ritual magick, where you don’t have a sympathetic representation of the target, you call an entity, tell the entity what you want, with all the intent and emotion stuff as part of that communication, and they do it for you. Typically rituals are proscribed and less open to editing, and need prior planning and often, more materials and ritual tools.
In practice, things tend to be a bit of both (a candle ritual is a good example of a blend of ritual and natural magick) and what you go with depends more on your personality, what you enjoy doing and how it makes you feel. Some people just adore the psychodrama of a good 2 hour fancy ritual, some do the exact same work with a bit of red thread, twisted paper and spit… or nothing at all. “You pays your money, you takes your choice.”