The grammar point for へ行くsays that ‘he’ and ‘ni’ are interchangeable but they have a different nuance to them.
'ni' has the nuance of 'going to' - it focuses on the destination.
'he' has the nuance of 'heading to' - it focuses on the distance traveled.
Then BP follows up with the following two examples to complete their point.
ジョンは学校へ行く。
John is heading to school. [Okay, ‘he’ = heading to.]
エルサは病院に行く。
Elsa is going to the hospital. [Okay, ‘ni’ = going to.]
Everything is great up to here. But then the examples for ‘he’ consistently uses it in the ‘to go to’ sense, e.g.,
Followed up with ‘to go to the station’, ‘to go to Tokyo’…and so on.
BP used ‘he’ for all the ‘go to’ examples instead of ‘ni.’ So if the Japanese uses these two interchangeably, why does BP point out this nuance. Furthermore, if BP decided to point out this nuance and followed up with that nuance in its two examples in the ‘About’ section, why didn’t BP use that nuance (‘ni’) in its examples? At least use it in some of the examples to show that either one could be used. But none??? What’s the reasoning behind this?
EDIT:
Out of curiosity, I deliberate used ‘ni’ instead of ‘he’ in the following review and BP gave me the yellow caution to change my answer.