Humans crawl before they walk. It is a foundational movement pattern that is innate for all people. Very few people, however, crawl after they grow up and stop playing. This is a huge mistake!
Make crawling a part of any balanced movement practice. Crawls can be done during warm up, as a strength and conditioning workout, or as a way to supplement other training exercises.
There are dozens of crawling variations. Start with the basic hand and foot (leopard) crawl moving forward and backward. Move up to inverted (crab walk) crawls and side ways (monkey) crawls. Make crawling fun and move in ways that feel natural.
There is no right or wrong answer!