Ive used signal for myself and family since 2016 Ive had some cell service issues (dropped calls while driving), or missed calls (no ring) in low service areas. But overall with very few issues.
However only 2 of my contacts regularly use signal. The majority of my contacts have iPhone and use iMessage. Most people I talk to also believe that the main difference between the apps are features/ui ux - they dont understand encryption as its invisible to them.
Several of my contacts argue that sms is the standard and like email there are many clients that do the same thing… Any app that cant sms will not reach the vast majority.
Ive answered many questions about signal over the years for my family and friends. When this article came out they contacted me concerned that I was using signal and suggested I get an iPhone so that I can use encryption. This revealed that while they at times show interest its to be kind to me and not because they are interested in what Im talking about.