Not so. Here it is part of a mixed pasture that includes some heavy feeders who like nitrogen, eg kikuyu.
Farmers of yesteryear knew
Here clover is seen as a bonus and it is encouraged and in some cases seeded into the pasture. It is nutritious and loved by both horses and cattle. If your pasture grows clover you certainly would use that land.
Improve the conditions for the lawn grass, and
Not necessarily. At certain seasons clover grows better than grass at others not so well. I have had clover in the spring so thick the pasture looked white and you could hear the hum of the bees wherever you went. Later in the year the same paddock produced abundant grass as the clover retreated, the paddock has dense coverage (except in drought) and shows no sign of choking out the clover which comes back each year.
You are giving clover a bad reputation which is not deserved but I doubt the OP is concerned about grazing animals so this is not really that relevant.
David