I basicly save them for event chests start with the good ones and work my way i suspect theres only 3 so players dont abuse it.

Very, VERY early-game I used to use them to pull out more stacks of Storm Rider before I really understood how resetting worked. I thought it was worth pushing as far as physically possible, so when I first started the game, no lie, I never reset even once for about a month. Just gaining XP and stacks of Storm Rider and pushing for those two or three more levels (yes, levels, not areas) per day. I thought I would lose all my trinkets and buffs if I reset, so I dumped everything I had into making the most out of each (well, one) run, so much so that my first reset was worth about 100 idols. It wasn't until I reset my first time that I realized how many resources I had wasted, and so I QUICKLY learned after that, that it is actually best to just reset around the time I stop insta-killing enemies. After that revelation, I became way, way more efficient with my playing.

Simple answer: As someone with 6.26 million idols, I use the warp buffs exclusively for event tokens. Aside from my shameful misuse of them when I started, the ONLY other use I've made of them was during other objectives that required a bit more DPS near the end of the objective, or when I wanted to push a few more areas for an achievement (back when hitting area 1000 actually meant something), but it has been a long time since those. No need for that anymore.

Greatest value I get from them is using them for event tokens during events including crusaders with abilities I intend to make use of. If the event crusaders don't really interest me, I'll still do the event areas, but I'll use "World's Wake" to grind for tokens instead just to save some warps. If the crusaders interest me, then it is worth trying to milk the event for as many chests as possible to get the crusaders well-geared, which means using warps to basically never need to touch World's Wake until the event ends.

I use warp buffs for getting more event items during event. Also I use them when I hit a wall to get more golds to upgrade my main DPS
I combine this with Storm Rider i.e after using a 4 hour or 8 hour warp buff, I immediately run Magnify+Storm Rider

Before using a war buff, I usually maximize the gold gain by activating Smart Investing (with Bat Billionaire) and run Savage Strike. For objectives with unstable formation and unstable DPS, I usually move to stable area or at least area with maximum gold gain