This is exactly the problem: Sometimes.
Will you trust your politicians to never do wrong? (printing)
Will you trust your banks to never do wrong? (fractional reserve)
Bitcoin fluctuates because its free, its rules won't change overnight, if the economy crashes no more bitcoins will be created than if it is in a "boom". The rules of Bitcoin do not change, this is why in the long run, it is Bitcoin the one that is stable, while all the others, are a time bomb waiting to detonate.
Bitcoin has nothing hidden. There is no foundation or developer able to "turn back" transactions or change its fundamental rules on a whim. This is the norm in fiat, and several altcoins. The people who don't understand Bitcoin, want to recreate the very same mistakes of fiat in their altcoins, because that's what they know. But they are wrong.
There is also no arbitrary pegging based on promises, that could be broken on a whim. Ie. Tether promising a 30% reserve... Yeah right. All pegged coins are garbage, true freedom means fluctuation, and fluctuation means true perceived value from buyers and sellers, no facades or "intervention" (State or private).
Trust that your government will never fail. But if it does fail, it is too late for you to withdrawn your trust... Are you putting all your eggs in the same basket? Did you never heard about diversify? Then why would you keep ALL your savings in fiat? So you could lose them all overnight if your politicians do fail?
Be smart already, and do the right thing.