Hi Daniel,
Of course, you're right about the native versions. If they exist, there might be a limited interest to run the windows version with Crossover. Unless there is some feature in the Windows version not found anywhere else, going native is the right thing to do. Mind you, you have selected a very small segment of possible software to run, no doubt based on your needs. There a tons of software out there that don't have Mac/Linux versions. Of course, you forget that when someone just switched from Windows to Mac/Linux, they might not want to buy a new licence of the same software they already have in a Windows version.
Where your comment mostly fails is that one might not want to pay for a windows licence. There are technical, legal and financial reasons not to want virtualization.
For instance, it doesn't matter if you use VMware, Virtualbox or Parallels, in the end, you must pay for a Windows licence. If you don't use Virtualbox for personnal use or use any other virtualization software, you must also have a licence for the virtual machine software on top, generally one licence per computer. It's beginning to be an expensive proposition. Also, you might want to read the licence, sometimes, there are limitations to Windows virtalization which might make that use illegal (according to the terms of the EULA).
Even in a dual-boot scenario, a Windows licence must be bought. You just can't run Windows without buying it first, unless you're a pirate.
Wheter your virtualizing or dual-booting, you'll have the hassle of maintaining the update of your Windows install, on top of the maintenance of your main OS. Crossover wins there too, as once it runs, it's less trouble.
While running Windows, you must also make use of other Windows software, like an antivirus software. Again, this is an expense which certainly defeafts your point. Granted, there is Microsoft Security Essentials, which is free, but that is fairly recent. Antivirus software is the first thing that comes to mind, but certainly, there are other unforeseen expenses. With Crossover, no supplementary antivirus must be run. Whatever you've got running is enough, and you've just save both trouble of maintenance and money.
As for Crossover, it's licence allows one instance to run per licence. Meaning, you can install it as many times as you want, provided only one copy runs at time. Already, this makes for a better deal. Also, unless you upgrade your Windows based software, you have no need to pay for Crossover again, you just keep running what works. With a windows licence, well you're out of luck when support runs out, as you might have serious unpatched security flaws that wont be fixed.
Lastly, please consider the gaming market. You might not want to make use of games, but it's still in favor of Crossover. For instance, most games are Windows only, and few are ever released for Macs (or Linux for that matter). Virtualization is generally not very good at 3d, so games (or anything else needing 3d) tend to just plain fail to run sufficiently well in a virtual environment. Crossover doesn't have that problem. If a game runs, it tends to run fine, and at good performance levels.
So my point is that native versions, virtualization or dual-booting aren't always the clear choice when you consider all aspects of the choice they represent, and not just what "works best" or fastest.
