"Got in" is a plain statement of fact.
"Hopped in" suggests a quick casual action. It could also suggest that the decision to go somewhere had just been made.
You could say "He hopped into his car and drove down the road to the store". Or "Tom was in a hurry. He waved at me and hopped into his car and drove away".
But you wouldn't be as likely to say "He hops into his car every day at 8 sharp to drive to work".