In one analysis, the final cause or intended end is likened to the eventual result. The lām normally marking a goal is then used where the sentence concerns the event's consequence.
The metaphor does not simply compare the letters of “lām” with some other particle. It concerns two relations: the connection between an act and its intended purpose, and the connection between an act and its inevitable outcome.
The label “lām of consequence” is useful, but it does not substitute for explaining that relational resemblance.