I have to wonder if the genericized definitions of these abilities has led to their overuse. For example, lords of men has a marshal professional ability for managing stables, but I have trouble seeing where this provides any benefit over abilities in animal handling and leadership. craft abilities also have a lot of overlap, where there is tool maker, farrier, and blacksmith, even though tool maker and farrier could both be seen as subsets of a blacksmith's craft...
They are very useful for allowing a straightforward ability to let you do all the important parts related to your job with one skill.
Consider the regular abilities involved as a bunch of coloured rectangles lined up in parallel on a Venn diagram, and the profession abilities being curved areas designed to pick out the specific subsets of two or three areas next to each other. This may help you visualise it.
After all, a farrier isn't strictly a subsmith of the blacksmith - making horseshoes and nails is a tiny subset of blacksmith, but handling a horse and getting it to present its foot without you getting kicked is a reasonably tricky task for animal handling, yet one farriers handle with ease, and a farrier can use their skill in place of chirurgy for horse's feet. Compared to trying to have some blacksmith, some animal handling and some chirurgy specialised in animal feet, having a profession: farrier makes a lot of sense, declutters character sheets for grogs, and doesn't mean that no-one under the age of 30 can be a professional in a field which requires little bits of several different fields. For a tool-maker, being able to use craft: tool-maker instead of craft: wood, craft: iron, craft: brass makes a lot of sense.
As always, it's up to your troupe to rule when people are trying to stretch a profession or craft too far.