I'm sure pens are very good indeed for those who need the convenience of something that already contains insulin..
What I don't like is that everybody who developes diabetes is automatically introduced to its control using a pen-injector, rather than a disposable syringe. And that's a bit like using a fountain pen before you've ever used a pencil.
What's so wrong with pencils? ... sorry, that should be: What's so wrong with plastic syringes?
I believe it's clear. Indeed, I'm pretty sure I saw you write something about it recently. (It may have been earlier in this thread, but I haven't looked.) In an awful lot of people's minds, syringes used outside of a medical environment are associated with illegal drug use.
And that very hard fact is itself, for me, a very good reason to MAKE A POINT of using the ordinary plastic syringe.
I'm shy about injecting in public, if I can avoid it. But I'm not at all shy about the syringe.
And if I had a child who developed diabetes, I'd make a point of ensuring that my child got to know and understand about a simple syringe before introducing the more sophisticated pen-injector.