1. Do I trust my phone to make purchases? No, I make the decision myself,
my phone is not smart enough.

2. Do I trust Google (or anyone else for that matter) with my payment
transactions? No, I do not trust entities that have a history of grabbing
user data from every search query, email, visited webpage, etc. to
handle my financial transactions.

3. How can these companies overcome these security and privacy objections?
Simple---do not harvest user data and sell to any and all bidders, keep user
data encrypted. Treat users as "customers" not "advertising revenue"!