An entry-level 10cm Railgun with its associated power plant gets you 4 shots on 3.3HS with your current reactors, very respectable for point defence even without turrets.
The Gauss line has important options (turrets, reduced size), but for fast craft it needs serious research investment before it can compete. The improved accuracy is desirable, but the bulk from weapons (6HS), turret gear and faster-tracking fire control adds up. Reduced size eats into their accuracy advantage.
As usual, there are other considerations and I'm not arguing that prioritising Gauss weaponry is wrong... but I'd need a specific reason to go for Gauss from the start instead of fielding Railguns as a stop-gap until my Gauss tech is actually good.
Considerations between weapon lines don't remain the same: I see Railguns as the low-tech option for point defence, but the high-tech option for secondary artillery (more compact than an equivalent laser loadout, but requiring more research and throttled harder by capacitor tech. I don't like investing heavily into Railguns, too limited).