I wouldn't trust the City gamblers with my hard earned.
You don't have to.
A pension is merely a wrapper (like a ISA).
What you invest in is up to you.
For example if you like property then you could invest in a property fund. You could also invest in bonds/gilts/cash.
A pension doesn't mean you just have to invest in stocks and shares it's just a wrapper that's all.
The underlying invstments (which can include cash) are up to you.

I get a 5% contribution from my employer plus 40% income tax relief which means I only have to put in 3% of my salary to get a 10% contribution (HMRC pays 2% in tax relief, employer pays 5%).
Frankly you'd be nuts to turn this kind of deal down especially if it's on some false assumption that pensions equals stocks and shares - that's simply false, you can pick whatever investments you want including cash.

Economic uncertainty around the globe
This is complete knee-jerk reaction stuff.
Stocks and shares are LONG term investments and can go up and down.
I'm not worried about what happened between June & August because I have 25 years til retirement.
If you are retiring soon then you should be moving your investments into safer types with less volatility.

To say you shouldn't invest in pensions because of short term volatility is rubbish.
Firstly you can invest in anything (cash, gilts, bonds, share, with profits etc.) and secondly equities are for the LONG term. If you invest in equities and don't undertstand they can do down as well as up then frankly you shouldnt' be investing in them, but you can still take advantage of the tax relief offered by pensions even if you want to leave it in cash.
Putting it under the mattress is risky because - there is guaranteed to be no return, no tax relief, it will go down in real terms and it could get stolen/soiled etc. (and yes I know you didn't mean it literally but the inflation and shortfall risks are still there).

Property or cash can be an alternative to more traditional investments but generally it's best not to have all your eggs in one basket and you need to consider the tax implications. The government offer tax incentives for pensions because they want to encourage people to save for their old age.