Yes, you’re absolutely right about improve the meaning of those actions. It took me some time to understand what do they mean.
To understand what’s behind them some concepts has to be clarified:
Any parameter of any layer is a Value Node. There are three types of value nodes:
Constant: they have the same value along all the time.
Animated: values are defined by waypoints
Linkable: Value is defined by its sub-parameters. Each linkable value node collects all the waypoints of its sub parameters and shows them all compacted. If there are two types of waypoints (i.e. TCB and Linear) at the same frame, the compacted waypoint becomes greyed (undefined). Sub-parameters are value nodes as well.
Convert: Converts a Value Node into a Linkable type. It disconnects from the previous value node then creates a new Linkable Value Node and connects the parameter to that new nalue node.
Disconnect: Creates a Constant value node based on the value of the parameter at the frame where the action is executed. It disconnect from the previous value node and connect the parameter to that new constant value node.
Export: Takes a Value Node (animated, constant or linkable) and labels it with a unique name. The value node is now known at any place of the document (by any layer) so any other parameter can Connect to it.
Connect: When a Exported value node is selected in the Child Panel it is available to be connected to any parameter, so the parameter is plugged to that exported value node. When you Connect a parameter to an exported value node, the parameter is disconnected from the previous value node. Parameters and Exported value nodes can be Connected only of they are type compatible (i.e. angle with angle and not angle with vector)
Link: When two or more parameters are selected at the same time (usually from two layers) it is possible to link the value nodes. In this case all except one of the selected previous parameters are disconnected from its value nodes and then connected to the value node selected from the selected. The decision on which value node is kept and used as link value node is taken inside the code and cannot be user decided (but it should be)
Value nodes are not discarded completely until all parameter that were connected to get disconnected. So when you disconnect from a value node it doesn’t mean that the value node is completely lost. Maybe other parameters still connected to the value node too, so it is not deleted.
Hope this doesn’t hurt any brain so much 
-G