Small craft can easily fill a number of roles- think of them as cutters or ship's boats under current use. Look at their advantages to see how they will be used.
Smallest Transit Drive- they use the same fuel efficient engines as warships and dropships, but in a smaller package
Smallest full life support suite- same as above, this is what actually gives them a patrol range superiority over ASF
Crew quarters- Unlike fighters, small craft have a multi-person crew and have a requirement for their own space- part of which is how it gets life support
Cargo- so you can extend the voyage if need be, or transfer small loads between ships in a fleet- DS/JS/WS.
No strict piloting requirements- Unlike ASF (or mechs) you do not have to be one of the special people to fly small craft
With that in mind, planetary customs should have a large fleet of small craft in most developed systems to deal with smugglers and your 'normal' pirates. Historically, most pirate ships were not heavily armed- they had to have enough firepower to threaten targets, but it was their boarding parties that really enforced their rule . . . which is why running into a navy ship was a Bad Day. So patrolling orbital space, runs out to mining 'colonies' or minor settlements, patrols around fuel harvesting stations (which would have pirate points at gas giants), and jump zone patrols- especially if there is no station of any sort- would be covered by such craft as the Taurian's Tigress.
Dropships that want or needed coverage (IE, no or overworked customs patrol) from planet to jumpship used to be escorted by Aquarius and Lyonesse small craft . . . IIRC, the main difference between them and the Tigress was they had shorter legs though I am not sure the modern (Jihad introduced) versions suffer from the problem that existed with earlier pre-ASF versions.
Another common use is going to be 'fleet' small boats. Designs such as the Landing Craft Mk VII and its clones would be used to transfer supplies & personnel between jumpships (who we have never heard of docking together afaik), warships, and even dropships. But dropships can dock to either and each other- so why use small craft? Simple risk avoidance . . . a dropship/jumpship/warships will take less damage from accidents during to docking with a small craft than the rest would trying to dock. Even that small risk can be negated since most of those 3 types have small craft bays. FREX, how many ships are at risk if you are using a DS to transfer a small amount of cargo between differen carriers at a jumpzone? Dropship 1 that is discharging the cargo, Jumpship A that Dropship 1 was riding on, Dropship 2 that DS1 is docking with, Jumpship B that DS2 is attached to, and then Jumpship A again when DS1 re-docks to keep going on it's previous route. Small Craft? Launches from DS1's small craft bay . . . lands in DS2's small craft bay. If it is a small amount of cargo, or personnel with their cargo, it is also more efficient to use the small craft b/c they will not have the fuel expenditure of a dropship nor take up the manhours diverted from a DS docking procedure for four ships as cited above. Further, we have examples of 'fleets' of transport DS shuttling staff between dropships for meetings as part of the work up to impending action when they are traveling to the jump point.
Personnel transfer, either between system bodies or between a settlement and the jump point. Think of the hostile environment mining colony trope in sci-fi (Outland, ST Final Frontier's Kitimer, Alien series, neoBSG, The Expanse, Babylon 5, etc) where there is somewhere that is cheaper (main reason) and more pleasant to live. BT covers this in one of the MWDA novels, the main settlement is on Kimball which has a Terra-like environment but a lot of the economic activity is focused on a world in a further orbit that has a hostile environment but rich in expensive metals. Besides the 'truckers' hauling bulk ingots from the planet back to factories on the main world or even to the jump point, you could also have mining crews rotating off the hostile planet back to the Terra-norm planet for health reasons. This maybe a trope but it happens IRL for the same reason . . . you have mining/drilling crews that are in the boonies or undeveloped areas that spend weeks on site and then get shuttled to somewhere more civilized (aka brothels & bars) to relax before they take up their next rotation.
Prospecting . . . spheriod small craft would be best for asteriod/moon/planetary prospecting. They have the same ability to have the extended trips as the customs patrol, cargo space for any specialized equipment, and spheriods will be able to land anywhere required easier than aerodyne. How do the big mining conglomerates know where to setup operations? Someone has to go out, poke at the rocks, analyze the results, and let them know where to go to make their money.