Ranked Battles give you more than double the EXP and money compared to Regular Battles... if you win anyway (the losing team gets absolutely nothing if the winning team gets a K.O. result), so I guess I don't really blame you for waiting. Not to mention, some of the popular weapons don't get unlocked till the later levels.
Going back to Ranked, Rollers are okay for Splat Zones, but I'd advise not to use them for Tower Control since people tend to use weapons with crazy long range (not just limited to Chargers (snipers)).