High-tech ships also don't have weapon mounts and OP to take advantage of Ordinance Expertise. And the flat bonus ends up a lot less significant for them since their weapons are balanced around premium flux stats to begin with. Eradicator gets ~180 bonus dissipation (+45%) with an average build. That's an entire medium ballistic weapon. Fury gets ~100 bonus dissipation (+16%), which is less than one IR pulse laser.
Now, high-tech ships arguably benefit more from the elite part of the skill, thanks to the higher shield efficiency, but nobody really elites Ordinance Expertise unless it's a cryopod level 7 or something. And slightly better shield is a lot less valuable than an entire extra weapon.
They still benefit from it. It can mean the difference of supporting it weapons or not. Fury is one of those that probably does not need it much given its mounts (probably one blaster and two missiles). I want it on high-tech ships that have a very hard time supporting a heavy blaster (or pulse laser in case of Wolf) even with max vents and other flux related hullmods.
Aside, it is very good on Ziggurat when I need to skimp on flux stats to fit all of the hullmods and fancy weapons, especially when Omega weapons get involved.
As far as elite goes, the player gets it, as do any automated ship with the skill. In case of Brilliant, the extra dissipation meant the difference between comfortably supporting HIL (plus autocannons and others) or not.
I generally do not give Ordnance Expertise on most of my officers because it is ranked sixth on my list and I can only take five. It definitely goes on any Remnant ship with an alpha core, though. I do give every officer Gunnery Implants unless I know for sure they will be stuck on a Gryphon (then I get the missile skills instead).