Very safe, for two reasons.
Firstly, the way it is legally set up – in addition to being issued by a large insurance company licensed and regulated in multiple jurisdictions, all customer assets are held in separate “segregated portfolios”, which means that your savings assets are held separately from company assets, and separately from other customers assets. This is not a company, group, or government savings plan which can have the terms and conditions changed by company directors or politicians. It’s yours, and yours alone.
Secondly, what it is invested into – all the investment funds available via this savings plan are from large, global investment fund managers who are specialists in their field. By default, all invested monies go into the iShares S&P500 Index ETF which itself is highly diversified, and if you want to choose other investment funds to personalise your own investment portfolio, over 300 funds are available from the likes of BlackRock, Schroders, PIMCO, Morgan Stanley, and more. The investment return you receive will depend on the investment funds you choose – the default S&P option has consistently, over several decades, generated an annualised return of just under 10% per year, and you can access all the data and analysis tools from Morningstar from inside your online savings account login to see the full details of all the other funds, as well as perform a portfolio X-Ray whenever you like to see the full category and risk rating of your overall portfolio if you decide to manage your investments yourself.