I don't think anyone claims that Lojban phonology will help people guess the meaning of its root words. Even if you guess that {klama} means "travel", you probably can't guess that it means precisely (x1 travels to destination x2 from origin x3 via route x4 using conveyance x5). As a native English speaker who's been learning Lojban casually for a few weeks, I find the phonological resemblances helpful mostly as mnemonics - {prenu} is easier to remember for sounding a little like "person", {nitcu} like "need", et cetera. (And remembering the place structures does get easier, there is a fairly consistent rationale to how they are chosen.)