I think we had this discussion before on this forum Chris. I've been telling people this for some years now, long before I started contributing to this forum, but few believe it until you do the math.
One of the cons of PBs is the idea the government allows, cynically, to circulate amongst naive people who compare it with the lottery, that "you can't lose your stake". Rubbish of course because the stake isn't the capital put into the scheme, it is the interest lost. But very large numbers of people do see it, wrongly, that way. The capital is in fact a repayable loan to the government.
It's better now but another of the PB cons was that you had to wait, originally six months, then I think three and now one whole calendar month before you could even enter the draw. Whilst the current period isn't that bad, the earlier waiting periods were an appalling rip off. They took the interest from you without even allowing you to enter the game! A staggeringly cynical government ploy that no privately owned bookmaker or lottery could get away with.
regards
Steve