A poorly chosen pseudonym can hurt your chances of acceptance. As a beginning writer, you have very little leverage with publishers as it is, so you may not want to muddy the waters further by using a pretentious or gimmicky pen name. Insisting on a blatantly obvious pseudonym may make you a one or two hit wonder, but won't give you staying power. If your own name is reasonably marketable and your work is meant to be taken seriously, you should not resort to a meaningless pen name. Later in your career you may feel the need to use a pen name for works outside your established genre, but you need a name and reputation first.
Pseudonyms can make artistic statements for the author.
Sometimes a writer takes on a subject that is highly controversial or threatens to expose secrets. Rather than remain anonymous or risk personal injury as the named author, you may want to use a pen name for protection. The pen name you choose may reflect some element of the controversy, or establish your credibility as an expert on the subject. In a different vein, you may choose a pseudonym based on a character you enjoy from literature or history. A well-chosen pseudonym can add an air of mystery or intrigue.