"When it comes to" and "with regard to"

Are when it comes to and with regard to always interchangeable? Is there any difference at all?

Both can be used to introduce a new subject of discussion; however, my feeling is that there is a subtle difference in acceptable contexts - "with regard to" is less appropriate when the subject has not already been directly questioned. For example,

When it comes to technology, I have no idea what I'm doing

would be fine, in the context of discussing, say, a new phone but the corresponding

With regard to technology [...]

would be inappropriate unless the question of the speaker's technological ability had already been raised but not yet addressed.

Both would be appropriate, in a context of say a board meeting, where "Technology" was an item on the agenda.