I suppose it depends on how you invest in the VB accounts and 3a.
Contrary to your employer’s pillar 2 you don’t have a general downside protection or even have a guaranteed return (for pillar 2).
Unless you basically stay in cash your VB accounts – depending on your portfolio – can go up more than the guaranteed return of your employers pillar 2, but it can also go down.[VB] Ditto for 3a.
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If you need withdraw at a certain point in time that is, say, less than ten years from depositing the pillar 2 money into a VB account, you might be looking at – depending on your risk profile – potentially significantly less than you put in.
After 10 years you statistically come out without losses most of the time, but I believe you need 20 years to come out without losses (with backtesting; future path might bring more bearish data points).
Anyway, point is not to present the exact case with lots of data, just that there is risk with a sufficiently short investment horizon (even 5-10 years) and the need to withdraw that you might end up with less money in your VB/3a accounts than you had planned. -
If you don’t need to withdraw at a certain point in time, you have a 5 to 10 year window (60 to 65/70) for (timing your) withdrawing.
The devil’s in the details as with the latest AHV change, some rules have apparently changed and as always there’s an Übergangsregelung. Look it up yourselves.
Anyway, going back to the initial question: I look at my VB and 3a money as birds in the bush while I regard my moneys and companies at my brokers as the cutest and most beautiful little birdies in my hand.
As the chicken bird that I am myself I mostly count on VB and 3a money arriving at my bank when I can legally access it, but I’m mentally hedging against the Bunderrat deciding that they’ll willy nilly tax it 39% (coming out of left field like the current proposal on federal savings measures) at the time I want it paid out because Switzerland just ran out of money somehow. 
[VB] Here’s a real life example for one of my VB accounts since I dumped part of my pillar 2 into it:
Finpension risk profile “medium” which translates to (in their terms) 5 year investment horizon, can handle 20% drawdowns, medium investing knowledge (at the time I chose the risk profile)
That’s about a 2% CAGR, which is still better than the guaranteed pillar 2 return, but only since the recent rise of the market.
Had I had to withdraw in October 2022 or 2023, I’d be looking at a negative total return of 10-11%.