Hmm. Tactical mobility - what I think must be most commonly considered by Warriors of the Clans - doesn't seem to require them. That said, it's a reflection on the Warrior Caste in general that strategic mobility might be most commonly found in the Merchant caste - where getting products to market means some degree of forethought, planning, and efficiency. So, I expect few would exist in a Jumpship fleet with the financial constraints faced by the Scorpions.
Which leave at least some required for high-priority missions, mostly urgent military ones where these expensive assets can be assured of some kind of escorting military unit to prevent some opportunistic Warrior going, "OOOH, SHINY!", and claiming it without a fight from the lesser castes aboard ship.
Military vessels... Given the Scorpion knowledge of history and the way they're portrayed in the Scorpio Ascendant Fiction, I think they could see the need for them in certain situations. Frankly - CAs, BCs, BBs, and DNs are a poor choice for them. Now, commerce raiders, fast strikers, any type of light Naval combatant, really, are a better use for all their fragility. Especially given at least one, maybe two, DS collars. The Vincent and Fredasa are good examples (minus the bloated cargo tonnage).
If it comes down to it before their abjuration, why not have their merchants lease a convenient vessel? You know the Sharks would be down for that in a heartbeat in exchange for a reasonable retainer. Particularly if they limit the potential liabilities (no fools, the sharks can probably reason out why the Scorpions would be interested in using such ships.) inherent to providing such a ship on a military mission.
Speaking of cost, would you consider a Retrotech Aquilla in a Escorpion Imperio-type of situation? You'd have to crunch numbers, but the situation might make such a ship a reasonable option. The numbers of vessels capable of limited defensive/offensive action in my mind makes up for the inefficiency compared to collars in a defensive situation. My own military adaptation of the Aquila carries 30 ASF and 20 small craft bays (Suitable for both ASF and the twin-engine small craft operating as torpedo bombers/assault ASF/BA transports in my AU.) and a limited cargo bay of 5700 tons. Of course, they use a Primitive jump core and you'd be faced with the choice between the high-cost 30 LY jump, or something more economical and less efficient. Tradeoffs either way.