It makes life interesting when trying to target PPC ads.
Yes. That's the perennial question. Since conversion rate is so low, is it a waste of money to target mobile? Should you bid adjust down? But then when you take into account that those people might research on mobile and buy on desktop, so you don't want miss them in the research phase.
And if you are in the travel industry, the chances are that the won't convert on your site anyway. They research on Trip Advisor, Yelp, etc, but they convert on Expedia, Booking.com, AirBnB, et ceterga. So that makes it even more complicated.