Any ambulatory mecha would have massive motion sickness issues for the pilot whenever it walked. Suspending the operator in a fluid would possibly dampen the effects of bobbing around on the vestibular system and dampen shock from collisions or high-G turns. At least I imagine. I haven’t played Peace Walker but that’d be my reason for that to be in the design.
Huh, that actually makes sense! It's worth pointing out that it also allows for a woman to be piloting said mech in a bikini and Kojima has terminal coombrain so that might factor in too lmao (maybe I'm not giving him enough credit idk)
It's not even a bikini it's just underwear. So...yeah, fanservice, just fanservice, albeit with an in-universe explanation as what Southloop said is pretty much it.
In Peace Walkers defense, you can also go on a swimsuit date with Kaz and get hot manbod so at least it's somewhat inclusive
this is why mecha need to be smaller, agile, and well-coordinated, like a ballerina or someone taking that rich person ettiquette book-balancing-on-your-head-as-you-walk class, rather than a huge stompy brutish thing almost falling over with every step (looking at you, battletech)