So: he's clearly non-ideological, which means he has a particular outcome in mind: he deliberately set lasers to be shorter-ranged. So he intends them to be used at short ranges; e.g. knife fights and missile defense.
If "knife fighting" is a valid ship combat scenario, then lasers might not be relegated to anti-missiles, and sandcasters might retain some value. (Indeed, sandcasters at really long "CT style" ranges may not have ever made a lot of sense. But that's of little or no concern.)
Since sandcasters exist in T5 ship design, Marc probably intends for lasers to be important as well; hence short-ranged space combat.
How that all works out is "key", I suppose.
Getting behind Marc's thinking:
We can probably divide most ships into two broad categories:
Military/Paramilitary/Naval and
Commercial/Private. In general, Commercial/Private vessels are not supposed to be shooting at each other, they are supposed to be engaging in trade, commerce, and transport. But the
Traveller space-lanes being what they are ("Age of Sail" analogy), such vessels need to be able to defend themselves against marauders or other potential hostiles and unknowns (especially on the frontiers). Thus they have armaments at need. But for commercial vessels cost is at a premium:
1) How much can a Free Trader reasonably expect to spend on weapon systems?
2) Missile racks need ammunition replenishment, which is a cost-issue,
3) Barbette weapons take up additional hull tonnage, and
4) Bay weapons (aside from being expensive) take up significant and valuable cargo space.
The primary tactic of the private or commercial vessel in general should be to avoid or outrun a potential adversary (i.e. get to the jump point or to the port before a hostile can close weapons-range), and fight only when that is not possible.
Military/Paramilitary vessels, OTOH, are designed for attack, and generally have a higher budget to spend from. BCS ships will be primarily dependent on their Spines (which are not dealt with in these rules), and are generally the province of the Imperial Navy. The ACS military/paramilitary vessels detailed here are likely what one would expect in Colonial and Planetary Navies. Such vessels are going to want to have the longest range weapon possible so that they can (ideally) get an enemy vessel within their targeting range while staying outside of their opponent's range.
All that being said, consider the prices of the various weapon systems. If we look specifically at those weapon systems of TL15 or less (i.e. those with which we are familiar from prior published
Traveller settings):
WEAPONS (T5.09 - p.301)
Range-Type | TL | Mount | MCr |
| | | |
| | | |
FR-Mining Laser | 8 | Turret | 0.5 |
FR-Pulse Laser | 9 | Turret | 0.3 |
FR-Beam Laser | 10 | Turret | 0.5 |
FR-Plasma Gun | 11 | Barbette | 1.0 |
FR-Fusion Gun | 12 | Barbette | 1.5 |
| | | |
| | | |
FR-Slug Thrower | 9 | Turret | 0.2 |
AR-Missile | 7 | Turret | 2.0 |
| | | |
| | | |
FR-Jump Damper | 14 | Barbette | 15.0 |
| | | |
| | | |
FR-SandCaster | 9 | Turret | 0.1 |
AR-Hybrid S-L-M | 10 | Turret | 1.0 |
LR-Particle Accel | 11 | Barbette | 2.5 |
[TC="4"][/TC]
[TC="4"]
Beams
[/TC]
[TC="4"][/TC]
[TC="4"]
Missiles
[/TC]
[TC="4"][/TC]
[TC="4"]
Exotic
[/TC]
[TC="4"][/TC]
[TC="4"]
Special
[/TC]
Note that (aside from the Exotic "Jump Damper" which we will set aside for the present discussion), by far the most expensive weapons are the Plasma/Fusion Barbettes, [FONT=arial,helvetica]
PA Barbette, [/FONT][FONT=arial,helvetica]
Missile Rack, and Hybrid SLM/SKM (which are likely more expensive because of the missile launcher). So both the Missile and PA are considerably more expensive (and the PA much more of a "tonnage-hog" than the other systems as well) - these are both of the long range attack weapons. And the [/FONT][FONT=arial,helvetica]
Plasma/Fusion Barbettes, while close-range systems, are both expensive and [/FONT][FONT=arial,helvetica]
[FONT=arial,helvetica]"tonnage-hogs" as well.
My guess is that the PA and the missile are seen as the long-range military weapons that a [/FONT][/FONT]military/paramilitary vessel would need for its mission, but which a commercial vessel "ought" not to need. The [FONT=arial,helvetica]
Hybrid SLM/SKM turret, however, is a nice option for the merchant or private owner who has some extra cash to spend to give them a little more "punch" should combat unavoidably arise (and be able to hit that corsair unexpectedly at long range with missiles).
[/FONT]