Using Wet Starting batteries for the fairly brief high amp draws instead of Deep Cycle AGMs is sort of clever IF you do have a way to recharge them right away.
Although vehicle batts sit there being drawn down by parasitic loads for days and days while also being under re-charged on short trips around town, they last quite a while. (Even without being put on a trickle charger between short trips.)
Hard to arrange an early recharge in ordinary RV situations where you need Deep Cycle batts that can take some 50-90s in a row before seeing 100 again. Maybe if you had lots of sunshine every day for sure.
Very little price diff between Starting and Deep Cycle Wet batts though.
If you had dedicated Starting batts for the big inverter draws you would still need Deep Cycle batts for ordinary camping. You have space for X batts, usually four.
Four 6s will do the job so no need for the Starting batts, but if you have only space for two batts, the AGM advantage for voltage sag comes into play, but if you choose Starting batts for that to save money vs AGMs, where is your Deep cycle 50-90s ability going to go? No space.
Two of those RV/boat 27s that are mostly starting batt might be a good choice --except they are such a PITA to recharge to 100% after doing a few 50-90s. BTDT--Never again!!!!
So, yes. If you really knew your scenario, you could pick just the right sort of battery bank(s) to suit
