There is a good feature to show only time entries created by owner, however if this option is turned on, there is no "Spent time" available on issue page any more.

I honestly believe it doesn't make any sense to hide it (if User.current.allowed_to_view_all_time_entries?(@project)), so as soon as we talk about time entries, that's ok to hide the entries themselves, but what is the reason to hide the total amount of already spent time (the value itself) for the issue?

I guess the "Spent time" could be displayed nevertheless the option and, for instance, not be a link (a href) to the times entries log if user has no permission to see all time log entries.

It would be nice if you can adjust it accordingly.