Being able to access the Snowpeak Ruins early can be crucially helpful in the game, especially since half of the dungeon is already skipped in an Any% by accessing the City in the Sky Early. Having early access to the Ball & Chain also opens up new strategies that can be used to defeat enemies and Mini-Bosses much faster than usual.
After the Lanayru Twilight is cleared, the ice door blocking access to the Peak Province is no longer there. (This wall can also be bypassed using cutscene diving if you have the Master Sword Early while still in the Lanayru Twilight.) However, you will find if you try and access the Snowpeak before due time, even if you know the route without the Reekfish Scent, you will get lost in the snow storm and be transported back to where you began. In order to overcome the snow storm, preform Map Glitch upon entering the Peak Province from Zora's Domain. This will prevent you from getting lost in the storm, which then allows for early access to the Snowpeak Ruins. It is very important, however, to remember to howl at the howling stone before you use the dig spot into the cave (to disable Map Glitch), or else your game will freeze.