1a) The benefit of leading from samsara to peace

What about these benefits?

These put an end to the kleshas of the ocean of samsara.
They clear away the fear and pain of evil deeds.
They conquer the karma and pain involved with conditioned formations,
Leading beings away from samsara and to nirvana.

Regarding liberation from the ocean of samsara, the Gandavyuha Sutra says:

Kye, son of noble family, bodhicitta is like a great ship that liberates us from the stream of samsara. It is like a warrior escort who liberates us from fear of samsara and the lower realms.

The Liberation of Maitreya (byams pa’i rnam par thar pa) says:

Son of noble family, it is like this. Relying on a heroic warrior, we have no fear of any enemies. Similarly, bodhisattvas who put their reliance in the warriorship of arousing the attitude directed at omniscience have no fear of any evildoing enemy.

The Bodhicharyavatara says:

Like depending on heroes when there is great danger,
Even after inexpiable evil deeds,
The instant we depend on this, we are liberated.
Why would those who are heedful not rely on it?

It clears away all suffering and evil deeds. The same text says:

Wanting to destroy samsara’s hundreds of sufferings,
Wanting to clear away the sorrows of sentient beings,
And wanting them to enjoy many hundreds of happinesses,
We should never let go of the means to this, which is bodhicitta.

The Sutra of the Instructions of the Glorious Great Vehicle (’phags pa theg pa chen po’i man ngag gi mdo) says:

Persons who enter the unsurpassable field of enlightenment without
the existence of even an atom
Cut off the bad path of going to the lower realms and all the eight states of lack of freedom.
Those persons are fully, completely separated from the path of gods and
human beings, and thus they completely abandon it.
Such persons will never be blind nor deaf, but rather their senses will all be sound.

In burning the firewood of karma and the kleshas, bodhicitta is like a fire. The former text says:

This, which is like the fire that burns at the end of time,
Certainly burns away great evil deeds in an instant.

The Biography of Maitreya (byams pa’i rnam thar) says:

By burning away all faults, it is like the fire at the end of the kalpa.

Moreover, by being made to attain buddhahood, we are led out of samsara. The Bodhicharyavatara says:

As for this, an immeasurable host of sentient beings
Will attain the ease of the highest state of blissfulness.