1 If you have ever used iBooks Author (free by the way courtesy Apple) then you will know that Author is seriously faster to use for creating multi-page leaflets / books. Drop all the text in and it automatically generates and runs the text across 20 - 30 pages, or lots more in seconds. Unless I have missed something with Affinity Publisher you have to add text box after text box and link them together. This is so tedious and imprecise.
2 The software background colour is black. This may be smart but is a serious usability issue. Research web designers know that text is harder to read when it is reversed out - and so they avoid using it. Trying to read the Affinity screens in a bright room or in perhaps in a bright Mediterranean / Californian environment is difficult to virtually impossible. Senior professionals like myself will find that when you can't raise the type size of the reversed-out description text - even though I use a 21 inch screen - they will need a magnifying glass is (my eyesight is not that bad either). For maximum efficiency usability must take precedence over making the software look pretty (and copying Adobe and others).
I know you plan other help videos - I suggest you have a simple speeded up leaflet creation with minimal voiceover - a 2-5 minute intro to the basics. An experienced user doesn't want to have plough through all the videos before they can get started.
I have been using DTP software such as Aldus Pagemaker, InDesign and QuarkExpress for some 30 years - and reckon that Affinity is definitely on the the right track. And no doubt a modest price tag will make it worth buying. But when I can generate a very professional pdf leaflet for free, many times faster on iBook Author (despite some vices) - it's far from an attractive option. Time costs the professional money.