Sure, its not as good as Swiftfoot Boots giving my best guy hexproof, but it still can regenerate from most targeted removal, and unlike the hexproof, it can also regenerate from damage in combat and some sweeping removal, such as Magmaquake and Day of Judgment
The Sphere is a lot less exciting than Oblivion Ring as it can't go in things like white weenie and the ability to hit multiple permanents is only really something that happens on tokens
Despite only six cards being printed that created Squirrel tokens at the time of this token's release, it was still featured as one of the Magic Player Rewards in 2002
I make the exception for lands on this list because these have such an impact on Standard and took multiple sets to complete
For example, think of Kenriths Transformation as purely a removal spell, with a bonus of being able to draw a card