For me it depends on where I am. If I'm on a public or business computer, I usually don't want to enter my credentials because I don't want them saved or grabbed by a key logger or anything of the sort. I also frequently read the forums on my phone while waiting to pick up one of my kids from their activities, it has problems saving the log in, and it's a pain to log in using the phone, especially if i use a password that has any non-alphanumeric characters.
Much the same for me. I enjoy browsing the forums during my lunch hour at work, but I don't want to enter my username and password there - our usage restrictions would forbid me from posting messages from my work PC in any case, so there'd generally be no reason to do so. This week's experiment has been rather annoying.