I'd say it does. kind of hard to explain but compared to say a plastic well palette it makes it a lot easier to dilute the paint without accidentally overloading the brush, and you have the entire wet palette to brush off some paint if you got a bit too much on. Either way, well worth building/buying one

i use all vallejo stuff mainly because they're more or less the only water based acrylics my "local" shops stock. vallejo primer is pretty ok to brush as they're pretty thin as is, however they're not like super resilient against scratches but it's better than just painting on bare plastic. their varnishes are an enigma to me and i honestly don't know what i did differently with the f-35 to make it that smooth lmao. But in general, i've found that diluting the paint is only half the battle, as controlling how much paint you have in your brush (preferably keeping it to a minimum) is they key to getting a finish that's smooth AND doesn't obscure any detail.

With regards to the mig-29, that was post shaded using a technique i found from here and here, pretty much just brushing thin layers of pastel dust/charcoal pencil dust around the panel lines. it's dead simple and while i prefer a more exaggerated effect (such as in the mig-29 and f-16) you definitely can keep it pretty nuanced.

lastly, some more f-35 pics. Hope this helps!