“Personal projects” does not offer you the same possibilities as other workspace. For instance I think you cannot use tags. @Bastien_Siebman could confirm that.
Therefore you can create another workspace for your personal tasks, but not use the default one.
I have a similar/related question. I’m an avid user/lover, and I’m leaving my organization in the next few months. What will happen with my “Personal Projects”? Will I lose access entirely when my organization account is de-activated? If so, guess it’s time to transfer them with Kothar I’d appreciate some insight into “offboarding”.