Well you're also paying for headstart if you want to play asap, although it has not much actual impact overall as you won't be getting a whole lot the first "week", and you have plenty of time before the second weekly reset to get your shit even if you don't do the headstart, if you play a bunch on the weekend.
Rest of the packs are kinda whatever yeah, Gold has a char slot but that's not necessarily super valuable right away(although I know I'd need one eventually to play random classes) and some costume shit which is nice if you like how it looks(I kinda don't care). Plat has more cosmetics shit and it's really just that you're buying. There's some consumables but it's pretty cheap stuff. They also all come with 1month of "sub" which is nice but since they all do it's not a defining factor. So the big difference in value is how many crystals you get for your money, which is roughly the same as buying crystals directly anyway, and Gold is very good value for that.
4000 crystals is likely to cost 40$, so you're getting everything else for only 10$. The sub itself is likely to be 6-7$, the char slot similar, a costume shit at least 7-8$ and the consumable 3$ or so, so even if you don't care about some of these, you're likely still getting a good deal.
Meanwhile Silver gives 1000crystals only, so you're paying 25$ with 10$ worth of crystals, a 6-7$ sub and a ~3$ pack of consumables and that's it. Which means you're actively paying for the headstart there, similar to bronze. So it's really as if you were buying bronze with sub+headstart, and then buying 1k crystal on top, it'd come out as almost the same, only giving you the consumables for "free" on top. It's very barely over its own value basically, and if you don't make use of the headstart for an advantage(aka you play at least 20hours before the weekly reset on thursday 1AM), then it wouldn't be worth it.
Platinum you're largely spending 50$ on the exclusive costume, the mount, with a few other things(exclusive but weak cards, stronghold decorations, wallpaper, some additional consumables like a single legendary gift, some more silvers, some una completion tickets etc). Mostly you'd need to want the mount and costume for it to be even worth considering, and I think the mount looks like shit personally so it would never be a thing(and the costume looks like crap on my "main" class, although I could use it on Bard). You also "only" get 7k coins instead of 8k(double gold price for double crystals), so you can consider 1k of the crystals were used in buying the mount/costume.
Ultimately it's also a matter of how much money you want to spend and all that. Personally I found Gold to be what I wanted, it's the price of a new game, gives enough crystals to play around the first couple of weeks to buy stuff I might want and comes with side stuff that I actually would have bought anyway(besides consumables, but that's not bad to have anyway). Headstart is also good just for reserving your name, since their naming system is absolute fucking shit, although hopefully someone runs a bot just constantly making characters with the dictionary names and deleting them, so they end up having to change it.