When I go to a user’s observation pages, I’m usually coming from the Identify when I noticed a new user for some reason (e.g. posting human artifacts, choosing a CV suggestion that seems obviously wrong, or even something innocuous like added the observation as an unknown and has a low total observation count) and I want to check their other observations to see if those share the same issues that first attracted my attention.
Not being able to see all their observations by default as I could previously means I miss a chance to inform them if their other observations are missing data that kept them from showing (like location or date, or failed to upload media) in Identify.