Keystone node- Struck Through need explanation

As the title states I'm having a hard time wrapping my head around it. It says increase critical chane by +1% for attacks. That's seems extremely low for a keystone. Especially when the ones around it are giving 15%. I've never claimed to be the smartest. So could someone pls help me out with this?

Its additive vs multiplicative. One gets watered down diminished returns and the other is applied after everything is said and done.

The 1% chance is added after everything else so you can think of it as say 25% more chance to crit, but also scales the more crit you have because its added after all the other crit bonus's.

Its worth for a crit build.

It isn't applied after everything.

It is applied to the weapon's base chance to crit, and is then multiplied by the 'increased' and more 'modifiers'.