I mean, there's something to be said for backlash against the cycle for fixating on combat (multiple speed of lights is definitely pushing it- one is +5 boots hilarity) and then advocating combat as a result but I do feel there's a tendency for the thread to assume that 'Mathilde an assassin, she is a scalpel she is a precision instrument that needs to be applied appropriately or be ineffective' is a fairly hard rule. But conventional combat is just another arrow in our quiver, one that Mathilde's actually pretty useful for even if you ignore 90% of her capabilities.
I'm going to lean on TT rules because it's an easy way to make a point- I'm sure Boney will treat it with a bit more nuance but if he didn't consider Mathilde's TT sheet somewhat representative he never would have given us one in the first place. Stubborn and Take No Heed for instance means the Undumgi would have done an admirable job of trying to fight to the last man had Mathilde fought among them and would have been almost impossible to break and killing Mathilde would have been pretty damn difficult. Fear and Terror make her unit immune to the same. She can potentially be a colossal pain in the ass to deal with that either requires obscene amounts of area of effect to put down, incredible luck in breaking her unit, or simply wearing her unit down to death.
I'm not going to present examples of where this might be 'necessary' because I know myself and other members of the killy crowd have made that sort of argument before but I think it's important to keep in mind even if you took away Mathilde's awesome sword she'd still be making major contributions in a melee engagement because despite us mostly seeing her capability as an individual operating deep behind enemy lines she's absolutely capable of making a unit into an anvil that needs to be broken down entirely and in turn being able to gank a lot of the sort of things that might be able to break said anvil. We see the accomplishments of the assassin and the wizard and it's so easy to forget the deed that put us on the map was simply being someone capable of exhorting men into a potential meatgrinder they were definitely starting to balk at. And I don't think her demonstrated ability there was a one time thing. So if the possibility of fighting at the front of the battle is on the table don't just look at it as a mistaken urge to try and be something we're not, but an option that would have us backstopping the morale of our front, attacking the enemy's morale, and being on hand to smack down any target that's causing too much while essentially hiding in the press of bodies.