Spectrus Killteam + Phobos Librarian

Recently I've been using a Spectrus Killteam with a Librarian in Phobos armor to jump around the map doing secondaries and sniping characters. It's a disruptive unit combo with a long reach, lethals, and precision, that also has lone op and stealth thanks to the Librarian. They are also more than capable of destroying a full unit of weaker toughness infantry in one round of shooting.

I get that they don't have some of the higher toughness and firepower of the indomintor and talonstrike, but they often make up for it in points scored, as well as their influence on the other player's choices. They're perfect for using Site to Site aggressively and removing the cheap units and characters which are usually scoring a lot of the points for your opponent. Forcing their larger units to either perform secondaries or ignore them will also gain you a points lead.

Anyways, I don't get why they're hated on so much when they've been quite a fun and valuable unit for me to use? However I'm only playing casual games between friends so in a more competitive setting they might lose out to outright damage and toughness.