I think it's been pointed out before, but their anti-matter steal/drain/disrupt/whatever it's called can be killers against carriers and cap ships, as well as support frigs. They also make good meat shields.

Part of the problem is that early game LRF make up the bulk of any fleet, and late game most players transition to heavy cruisers.  Both of these absolutely murder LF.  As a result, it's just not smart to build these guys in bulk.  Used sparingly they're decent, and if your enemy is going crazy with carriers a good mob of them can be useful, but in general you want to use them as specialty units.

The LF's speed is essentially negated by turn rates.  After a few seconds, any battle devolves into a big clump of units shooting at each other, and most movement is actually turning, at which LF has no advantage.

Honestly, what are those 150 people even doing?  The ship has like 1 thruster and two lasers.  It has a shield system, a self-repair system, and a phase-drive system.  Presumably it has a captain.  That's 5 functions (most of which are probably controlled by computers...) plus a captain.  Why do we need this many people again?

Also it's a poor meat shield in practice.  The main damage of an early-game fleet is LRF, which just rip LF to shreds.  They're good at absorbing attacks from strike craft, but your opponent would be stupid to fast-tech to carriers against a LF masser.

Just try sending like 2 dozen LFs against his crucial support cruisers (i.e. hoshis, guardians, subverters). They'll be first crippled and then killed. You'll most likely lose the LFs if they're in the midst of the battle, but most of the time they won't be. Support cruisers die really fast, and after that you send them after his carriers, which are most likely positioned at the edge of the grav well. If his LRFs follow - sure, your LFs will be toast. But that's the purpose of a counter. If you got the same amount of LFs than he does of LRFs, you'll most likely inflict a similar damage on his carriers than he inflicts upon your LFs. Plus, his LRFs are out of the battle, which commonly takes away a great bunch of firepower. Never ever underestimate the AM-ability of the various LFs, it can definitely turn a battle. Imagine a fearsome TEC fleet with massive hoshis or an advent battleball without AM. Feels awesome, trust me

Or stealing the AM from a Marza..that's fun as well

Regarding your strategy: LFs are more similar to support cruisers regarding their role in battle. You can't base a strategy solely on them, since they are (really) hard countered by LRFs, which everyone will most likely get early on. Sure, they counter scouts (even though they have a hard time chasing them, but carriers are harder to get), but for that they don't need the AM tech.

Yeah, pardon my mistake, I got to know that today as well

They're still useful

The reason lf's aren't used that much is because everyone and I mean everyone goes straight to long range frigates. Light frigates are rarely the best option because the counter to them is the best early game ship out there.

I will say this. Light frigates become useful when you finally play the counter game. He makes lrf's. You mass scouts and carriers to counter, so he makes lf's and flak, so you make lf's and long range frigates, he makes lrf's and scouts. The chain finally gets broken when someone finallly makes the heavy cruisers.

It's not useless. It's just that everyone goes straight to lrf's.

There IS an effective strategy for LF use. Its called Imperial Guard style. Thats all you need to know