Mito made great contributions in the way of protecting Konohagakure after becoming the beast's jinchūriki. She was also the one who realised that in order to counter Kurama's ability to overwhelm his jinchūriki with negative emotions, thus taking control of them, love was needed. This was information she passed on to Kushina Uzumaki, which in part helped the young woman to be able to subdue the beast within her and later helped Naruto Uzumaki to subjugate the beast.
Trivia