Can't Login via OpenID from Mobile Phone?

Question

Is it that third party authentication in general and OpenID in particular can't be used to login to websites, if I'm on mobile phone?

The reason I ask this is because buxfer doesn't seem to allow this:

You will not be able to login to the mobile/iPhone site, Facebook application or Firebux because your password is not stored by Buxfer. To explicitly set a password for your account, login and click on "Settings » Password"

Is it a limitation of the website, or OpenID?

Answer 1

No it is because their mobile/iphone site, facebook application or firebux doesn't support openid as their regular webapp does. I cannot say why or if it is because openid is harder to implement on these platforms but it is not a limitation of the openID format.