With a thermal profile of 1.8W when operating, it won't be extremely friendly on battery life but isn't astronomically bad either. It'll definitely get hotter than a 5400RPM unit, but for drives at this speed they probably aren't intended for low-power, long battery life units anyway.
Laptops made huge headroom into the “replacement desktop” category with large advances in mobile CPU and GPU technologies. Today, it's easy to get a laptop that has CPU and GPU performance on-par with a desktop, perfectly suitable for demanding tasks like games. One area it has still suffered in, though, is hard drive performance. The majority of laptop HDDs spinning at 5400RPM simply can't compete with a very cheap desktop competitor, and 7200RPM drives were relatively rare. Now they are much more commonplace and becoming affordable, making laptop drives that can compete with desktop drives easier to find.