Certainly the Firebeetle may have not seen as much success as the ever so prevelent Units as the Mercy or the Corsair but it might be due to be being stuck on Land for the most Part and the Cybran transports absolutely not being the Best for huge Drops (given Seraphim transports have more slots and can still drop T1 Arty with good payoffs if the transports can fly through gaps in AA) there certainly could be place for the Fire Beetle..
if it were only that tad more durable and faster since even with a successful drop of a good amount of Fire Beetles they are quickly dispatched due to not being as blazingly fast as an Mercy and having to fight Land Fortifications like other Tanks, the ACU and maybe PD
on the Flipside they are about as cheap as some TML butreally arent worth their "wasted" Mass in Tanks