An intron is a region of a gene that does not code for amino acids that make up the protein encoded by that gene and does not stay in the final mature mRNA molecule following transcription.
Exons and introns make up the majority of protein-coding genes in the human genome.
From this perspective, introns are extremely important. In the age of new exon mixtures, they serve as recombination hotspots.
Overall, they're in our characteristics because they've been used to build new qualities more quickly during development.