That's really what it has over iWork, which works just as well across devices that can run it, but is Mac specific. If someone wants to get that same level of compatibility out of it, they'll have to go with an Apple geared office setup, which would likely end up being more expensive up front than a 365 subscription would be over time.
For some people, it will be more expensive. For others, it'll be considerably cheaper. Like anything, it depends upon what you need.
As for people not considering alternatives, well hell, that's a problem all companies would love their customers to have, Apple included. They have the mindshare, and they're gonna capitalize on it. I can't fault them for it, so long as they don't become outright abusive about it.
Though I won't give you or anyone else any flak over suggesting alternatives. I can think of plenty of instances where someone investing in Office would be complete overkill, and iWork would work just as well for them, if not better, considering it's ease of use. All that matters in the end is that the money your spending is appropriate to the overall value the product provides you. For people who do need it, the 365 sub is not a bad deal in the least. You're getting quite a bit for the money, and gaining access to services that aren't offered by any other suite.
