2.2 Bladefall/EK Help

So this is my current build:

https://www.pathofexile.com/passive-skill-tree/AAAABAYAAAceDkgPqxGWFe0WvySLJpUqCyo4SVFUvVVLXEBd8mHiZJ1qjHBSdf2Eb4nTjDaP-pUuloui2bDYtUi5k8MJwzrIFNRC1bnr9fDV8h31bw==

I was thinking of going to this:

https://www.pathofexile.com/passive-skill-tree/AAAABAYAAAQHBx4N0Q5ID6sRlhXtFr8ZihqPIG4kiyaVKgsqOC0fPV9BlklRTLNQMFJTVL1VS1XGXEBd8l-wYeJjQ2SdaoxvnnBSdf13B3_Gg9uEb4TFhxOJ04w2j_qVIJUulouXlZu1nKSio6LZrrOw2LVIuZPB88MJwzrIFMpK0PXUQtW544Tr9fDV8h31b_ba-wk=

Puts me around level 60.

My questions are:

I seen a build where Nightstalker was chosen increasing phys dmg dagger and crit chance with daggers. How does this help/effect Bladefall/EK? (Elaborate a little please)

Any changes that should be made to my current build or future goal please show.

This is possibly my first post where I am confused about a mechanic. Thank you in advance :)