Au Contraire.
If someone wants to daven from his i-phone, Kol HaKavod. It means more Siddurim for other people (who don’t use a phone) to use.
I personally daven from my siddur (well a few, but that’s a different matter).
However, it’s often the case that Mispallelim come to the Bais Medrash and can’t find a siddur (since most are taken).