Simca's abilities have just been made clear, she's not suited for fighting, the same probably goes for the majority of Link Tuners.
It was said earlier that it was because of her charm 'n' charisma that she was able to gather so many Stormriders, that her true talent(or something along those lines) was to make teams.
There's some other possible reasons, but that would be treading into spoiler territory.
Volume 17 goes on sale sometime within the next week, I believe. Hopefully Kuu'll get HQ scans of 'em before they finish up with v16.