Slow cooking is a time honoured technique, it not only provides a great tender meal from tough cuts but, the slow cooking meant the meal could be cooking without needing to be watched.
A Crockpot or Slow Cooker is a great tool for slow cooking and in BBQ we are trying to cook slowly and have the meat break down the same way but not always in a bath of liquid.
Temperature control is the key, no matter what you are using to cook in. In a crockpot, or oven, set the temperature and walk away.
In a BBQ maintaining temperature is a manual process, unless you use a Digital Temperature Controller.
I’m looking for 100°C (212°F) to 160°C (320°F), this is a small charcoal fire, or in a gas BBQ maybe two burners on and the others off.
In a Kamado it would be a low fire with a deflector between the fire and the food, this tempers the direct heat from the fire.
I’m a fan of Cast Iron, it holds heat well and transmits it to the food slowly.
I use an old Cast Iron Frying pan with the handle removed as a Deflector, Drip Pan, Water pan and Roasting Dish!
A good “Leave In” temperature monitor is a great tool to have also.