Well, it's the only software the have right now except Pro... which costs $60-$149 more. Other than the length of support issue, most users don't need the extras in Pro, so why should they pay for it?
Presumably, that's because MS considers MCE to be a consumer / multimedia, rather than business, product. So, if such MS support between 2-7 years from now is important to you, then, I agree, you don't want MCE.
However, XP MCE is, in fact, a superset of XP Pro. On my Toshiba's Sys Info - System Summary screen it says OS Name - Microsoft Windows XP Professional, Version - 5.1.2600 Service Pack 2 Build 2600, etc. Also, I have access to Pro features such as Remote Desktop and Encrypting File System, which are not available with Home.
Apparently, the only thing that MCE doesn't have that Pro has is this: MCE can't connect to a Windows Domain hosted on a server running Windows Server OS that's acting as a Windows Domain Controller.
Aside from that esoteric tidbit (and that Vista-world extended support), you get the best of both worlds -- full XP Pro plus some very cool multimedia features.
