Hi Jeff, is it Pega's best practices to use the Global Lookup tables as data storage and to not pass table data in and out of automations but instead, just access the global lookup tables directly?

Adam,

There is no best practice here.  I think the best way is determined by the number of parameters and the use case.  Local variables provide thread safety for your automation.  If an automation could be executed more than once concurrently (triggered by an event for instance) then you will want to pass in the values.  If this is not possible and there are a small number of values to pass in, using parameters makes sense.  If you have a large number of values and the automation is not going to be executed concurrently then using a table is a convenient way to avoid unnecessary copying of the data.

In your projects we used this practice due to the volume of data required - not due to a best practice constraint.

Jeff