So, are you saying that the existential understanding of reality is not helpful?

I find writers such as Nietsche, Sartre and Camus very helpful in enabling me to make sense of life.
Is this not an advantage of the belief, although it is subjective.

It depends on what you mean by advantage. Do you mean it is not of use in critical argument, the tool of the philosopher? I would say that the existentialist writers should be seen primarily as artists. While philosophy can be a critical, objective examination of truth it is also a part of an arts based search in providing subjective meaning for living.

Jack Cummins: So, are you saying that the existential understanding of reality is not helpful?

I'm not seeing it as an understanding of reality, but an understanding of the sequence of events that are used to move within the confines of reality. Do I have a notion of the consequence I am expecting when I post on this forum? If I had, then I act, thus expecting a reaction/reactions and ultimately guiding further acts and reactions to reach an expected conclusion. Politicians understand the existential way in which we live but do not always get the consequence they are aiming for. Usually other actions are taken by others and the politicians becomes the reactor and the consequence may become an unintended one. I've noticed some people are oblivious of the existential meaning of life but are very good at getting the consequence they seek by acting almost subliminally oblivious to any need for understanding.

Jack Cummins: I find writers such as Nietsche, Sartre and Camus very helpful in enabling me to make sense of life.Is this not an advantage of the belief, although it is subjective.

Making sense of life is like understanding the rules of the game but that has perhaps little impact on how well you can play the game. I can understand the rules of chess but the next step of playing it well means moving to another level perhaps.

On the other hand, rather than conquering battles it is better to live extreme existentialist dramas as the raw material for artistic creation. Life would not be the same without the novels of Camus and the other existentialist writings. They say so much more than many dry writings of a lot of the philosophers.

I also recommend The Outsider by Colin Wilson if you have not read it because it gives a brilliant critique of existentialism and artistic creation.