A Scion Meltagun Command Squad = 80pts for 4 Meltaguns, and if they are with the Iotan Gorgonnes, can be deep striked with Daring Descent (1CP) 5" away from a target (within Melta range). I killed a Pask Punisher with that today, then the following turn was able to take out the other Tank Commander the same way. Kappic Eagles can do the same with Precision Drop on T1 using a Valkyrie, and hit on a 2+...
Not sure if you're continuing the comparison to Eradicators, but if so, you're needing a specific subfaction and then either CP
or transport support to get that performance starting turn 2 at the earliest. Meanwhile Eradicators get the same damage:cost ratio, can deploy on the board and start shooting T1, don't have to worry about being screened out, and are astronomically harder to kill and more likely to survive to the next turn.
Otherwise yeah I've been using Precision Drop as a delivery mechanism for melta Scions, and it works pretty well. I do find it's a bit of a toss-up between Kappic Eagles for disembark bonuses and making HSVGs useful, versus Iotan Dragons for making HSLGs useful and giving plasma Scions a bit larger lethal range. Either way, Elimination Protocol Sanctioned is a significant force multiplier for meltaguns, which normally suffer from only wounding on 4s against tough targets.
I normally run my meltaguns in full squads for casual play, but two Kappic Eagles Command Squads with full meltaguns dropping out of a Valk and being ordered EPS are looking at 22.5 wounds against T8/3+- they won't quite kill a Knight due to its invuln, but they will bracket it. Not a bad return for 200ish points of dudes and a transport.