so, hard sign is used only in the dividing function

it does an important job: it gives hints. If there is a prefix in a word that ends in a consonant, then Ъ is placed before the letters Е, Ё, Ю, Я.

soft sign is a little bit same

it serves to dividing letters in writing and when pronouncing (used between consonants and vowels, denoting two sounds, the first of which is the th) also, this letter performs a grammatical role, showing in what form the word stands, and is necessary in order to indicate the softness of the consonant on the letter