hah, I am soooo badly prone to this in every game I play-- not wanting to use the currency, items, or skill points because what if I realize I need it more for something else later?? Except I say that about anything and often there is never a One Best Thing that feels worthy of it. It's a struggle and I just make everything harder for myself. But it's all worth it! Because at the end of the game I have..... a bunch of currency and items in a game I've finished and no longer have a reason to play anyway!** Wonderful.
Okay, I am learning to be less extreme about it than I used to be, but still, I understand the feeling. I feel like the key factor to me feeling comfortable spending something is "is there an infinite amount of it available to me and the only thing I need to do to obtain it is spend more time playing the game?" If so, I can be a little more chill about it, because the worst that can happen is that I spend more time playing the game, which presumably I am enjoying anyway if I am playing it at all. Where it still gets stressful is in games where I don't totally know where the resource is coming from or have a reliable way of obtaining more of it, or when I am forced to spend the resource for an opportunity to gain more of it (octo expansion actually stressed me out in this regard in the beginning, because I was struggling to still learn basic mechanics at the time and worried for at least the first several stations that I wasn't going to have a reliable way to farm up more points if I needed to.)
Anyway, all that said, the impression I get is that you can get pearls just by making attempts through the spire, in which case I'm not too worried because I can always replenish them by just making more attempts, which... I'm going to be doing a lot of anyway, seeing as that's essentially the entire game. And if that's the case, it's probably better to spend the pearls than hoard them, because spending them, even on something suboptimal, will presumably give you the ability to progress faster and collect more pearls at a faster rate, while hoarding them is basically forcing yourself to 'suffer' the exact consequence that you fear (of having spent them on something pointless and having to play longer to get more), only you're actually sitting on a pile of the very resource you desire.
I suppose this could also be general financial advice, context and economic situation depending. (Do not take financial advice from random 8-legged strangers on the internet)
** This isn't entirely true, sometimes you also have the satisfaction of essentially having played the game on 'hard mode', but when that isn't your goal and is merely a side effect of resource anxiety it isn't exactly as satisfying. Similarly, sometimes resource-hoarding is actually a good way to intentionally keep a game challenging for yourself-- you don't hoard out of anxiety but instead you get as far as you can without spending and wait until you've hit a serious wall and spending the resource is the only way over it (I did this with the upgrade points in splat3's single-player mode). But I'm not talking about either of those situations here, I'm talking specifically about hoarding out of fear of resource scarcity.