1) True. Security and convenience are most often non compatible goals. If you value convenience more than security, feel free not tu use OpenBSD.
2) True again, but to make your Linux system totally secure, you have to do a great deal of manual configurataion, which not everyone has the time, the will or simply the knowledge to do. OpenBSD is secure by default.
3) True again, but how is it OpenBSD's fault is so few vendors are opening their drivers ? And the few driver it has work perfectly. For example, my RT73-based WiFi USB stick was recognized out of the box in OpenBSD, which was not the case in any other OS.
4) Which features are you talking about ?
5) Rubbish. Unless you bloat it yourself, it is way faster than Linux in every way.
The End : you don't know what you're talking about.