Last I checked, people couldn't see what was happening through linkpearls.
There's still a lot of merit of having field commanders. Being able to see what is happening to be able to direct forces. Being a strong fighter to help mitigate losses by clearing out more of the "Fodder" enemies. Being a huge morale boost for your troops. Being able to deal with threats as they appear (For example, do you think just sending a message over linkpearl to people in Rhalgr's Reach to GTFO would have stopped Zenos and the Imperials from slaughtering everyone if the WoL wasn't there to engage him to at the very least, buy time for others to retreat?)
This is a setting where combat ability matters a lot. Retiring to become an armchair general is not a good tactic unless something happens to limit your combat potential (Such as losing an entire arm, which is literally the only reason Raubahn doesn't get involved. He wants to, but he cannot because he's not strong enough any more).
This is also implying linkpearls are actually used. Yet after say, Ghimlyt, everyone returns to Raubahn to inform him of what happened, so he can plan out the next move... To say nothing of Alisae deciding herself to press the attack with WoL, Hien and Yugiri. Acting field commander taking charge of the situation as it changed rather than linkpearling to "Supreme Allied Commander" Raubahn to notify him of the situation and let him give the order to press on... (With the call happening and then the further acting field commander decisions to pull back and report to Raubahn and get Alisae to safety)
And again, THEY LITERALLY HAVE THE DATA FOR 8 MORE RANKS FOR US TO ATTAIN.
In the game code, they have the ranks, including their insignia's already there. It's not like I'm guessing about additional ranks, they literally have the data for:
Second Storm/Flame/Serpent Commander
First Storm/Flame/Serpent Commander
High Storm/Flame/Serpent Commander
Rear Storm/Flame/Serpent Marshal
Vice Storm/Flame/Serpent Marshal (The same rank as Pipin)
Storm/Flame/Serpent Marshal
Grand Storm/Flame/Serpent Marshal
Storm/Flame/Serpent Champion
Implying they have plans to allow us to eventually get promoted. Likely not being merely a pencil pusher role, because that wouldn't make any sense for our characters.