My life is vastly enriched by friendships with people who have come to the UK as immigrants and others who are the children of immigrants. They include people who came seeking asylum and people who came seeking a better life. My life is enriched by other friends who have emigrated, through whom I have valued networks of friends in many other parts of the world.
Economically too, migration matters. People sometimes talk as if there are a finite number of jobs and immigrants increase the competition. This is nonsense. Immigrants come, they work, they buy things, their presence boosts the economy. They create more work and more possibility.
A study published in 2014 showed that European migrants pay substantially more in taxes than they take in benefits. They arrive having finished schooling, and all the costs to the state of bringing people to adulthood.