The difference between using Gerund and Abstract Noun is "the way to use it".
It is true that Gerund is a form of adding -ing to a verb to form a word to "be just like" a noun.
For example, arrive (V) --> arriving (N) ? (How about "arrival (N)" ?)
As it has been said Gerund is formed to be like a noun, it can, in fact, a noun and sometimes an adjective.
For instance, consider the following sentences
- I have to clean the room because of your arriving. (Incorrect)
- I have to clean the room because of your arrival. (Correct)
Roughly, it seems fine for both but you have known "arrival" is a noun. Why do you have to use "arriving"? When would "arriving" be used?