he'll probably be getting Trail Commission every year on the value of the fund for ever.
Might be 0.5%, might be 1%, might be less, shouldn't be more. It will help to fund his comfortable retirement, especially if over his career he manages to handle a hundred clients, each with a million-pound pension, and gets 1%, or even 0.1%, trail off each of them...
hence why I prefer the fee-based, no commission, low charges route.
I have a simple SIPP myself, which excludes commercial property, fine wine, Old Master paintings etc, so is very low cost.
I don't work in Life and pensions any more, but formerly worked for a well-known company in Norwich, and another in an large, red-brick building in High Holborn, and it was very noticable that the early SIPPs were designed to maximise revenue for the company and the salesman advisor
For my own schemes, I pay a lot of attention to low charges and low costs. They add up over the 20 or 40 years life of a pension plan.
Out of interest, have a look at the Schedule of Fees on www.alliancetrustsavings.co.uk/pensions/full-sipp/
this one does not pay commission, unless you ask it to, so is not often sold by Independent Financial Salesmen Advisors
Others are available.