I can listen to Larry Graham all day, Marcus Miller for 5 mins and Mark King for 10 seconds.
IMO it's just one of the techniques we should all know in order to become better and more complete players. The best slap players use it sparingly and effectively, ie Chuck Rainey, Alex Al, Reggie McBride and Nathan East.
I have several regrets in my bass playing life and one of them is that I never managed to learn to slap, but I'm in good company, ie Wilton Felder, Willie Weeks and Duck Dunn.