Robo-advisors emerged in 2010-2014 with the original pitch that algorithm-driven portfolios could beat human-managed funds while charging much less. The 'less than human-managed funds' part is unambiguously true: active UK retail funds typically charge 1.0% to 1.5%, and most underperform their benchmark over 10 years. Robos in the 0.40% to 0.75% range beat that comfortably.
What the original pitch missed is that DIY tracker investing has become dramatically cheaper since 2010. Trading 212, InvestEngine, and Vanguard have driven all-in DIY costs to 0.22% or less. The 'much cheaper than active funds' angle is still true, but the 'simpler than DIY' premise gets weaker every year as DIY tooling improves.
The wrappers themselves haven't changed: a robo-advisor inside an ISA is still tax-free, the
£20,000 annual ISA allowance applies the same way, and FSCS protection works the same as any other UK investment platform (£85,000 per provider on the cash element, and underlying investments are held in nominee accounts segregated from the platform's own balance sheet). The robo wrapper itself does not change the underlying tax or protection regime in any meaningful way.