I think it is a substitute for the match day programme that the club no longer prints and sells. An enterprising fan group or just local printer sells a programme for £1 but I never buy one. In fact I never bought a programme anyway and I think that was the case for most fans. Apparently it wasn’t worth the club printing and selling the old official programme as sales had dwindled over recent years and it was a money loser.
So instead, the club produce this digital programme and send it to all fans who the club have registered email addresses for. I get one every week but I never even bother to open the email. Does anybody? Clearly the costs of producing a digital programme are very small but the advertising space can be sold to willing buyers. Who knows?