You put money in a pension to secure the huge tax benefit (especially for higher rate taxpayers) versus deprive yourself of fun in the here and now. You put money in a pension then get taxed on 75% of it when you retire versus put money in an ISA and pay no tax when you take it out.
But why shouldn't you be taxed on income? You get your personal allowance, currently £12,500 tax free, and 25% of your pension tax free (so, on the £500k we're talking about that's £125k free of tax, you could live on that for five years, so five years without tax!).
And then basic rate up to £50k, 20% (using current rules, obviously we don't know what tax rates might be in the future).
I "save" 40% tax by putting in the pension now and will only pay 20% when I draw it, so it's 20% up straight away. Plus the two tax free amounts.
And sorry, but it's not "put money in the pension and deprive yourself of fun now", you can put some money in the pension and have fun now. Split the money you have.
Money you put into an ISA has already been taxed (assuming it was earned), and you don't get 25% of that tax free. I use an ISA too, because I can take the money out any time. There is no tax saving putting money into an ISA other than you don't get taxed on income or growth/capital gains. I use it to avoid having to report on my investments on my tax return, saves a ton of paperwork.
The not living to see it is obviously a tricky one, my family does have longevity on both parents sides and I'm so glad my dad's pension was good and he saved loads and I never have to worry about my mum now dad has died.
Not having a spouse and kids makes my retirement needs different of course.
I'm not waiting until 67 to retire. I have every intention of downsizing my career at 55/56 and stopping around 60!