Greater choice and variety of mates increases a female's chance to produce more viable offspring.
This led me to the question: "How sperm parameters are connected with entity parameters?"
Actually, sperm parameters are usually: motility and morphology. I am speaking about a single sperm, therefore any parameters involving their count or parameters of semen are not included.
On the other hand, what helps a particular entity to survive is determined by many parameters. Some of them are: speed, endurance, strength, agility, stealthiness and savvy. It is hard to find out how strength of being is connected with motility or morphology of sperm it has been conceived. And even less obvious is the connection of stealthiness with such sperm parameters.
But since sperm competition exist, it helps in natural selection, therefore there must be a connection. But how does it really work? How are stronger/faster/stealthier/etc. entities are the product of more motile or better in morphology sperm?
After some thinking about it I think that if there is some correlation between sperm parameters and genome, it can answer the question. E.g. presence of gene that increases fitness of organism makes sperm faster.