in the beginning of brawl stars, the very first throwers (barley and dynamike) were called "lobbers". And when you lob something, you throw it over like a wall or something. They changed the name to throwers because barley, tick, dynamike, and sprout throw stuff over walls.
Mr.P just has the ability to shoot out a suitcase that BOUNCES UP into the air. He doesn't throw the suitcases up- thats why.
I hope this answered your question