When comparing against something like a Pixel running GrapheneOS, it's honestly a bit more puzzling to me. Granted, I'm definitely not the audience for this, but with G_OS you can do most things that a regular phone can do, without taking several minutes to install Firefox.
As much as I love privacy (going as far as having a semi-random username), this phone is a bit puzzling. I hope someone can throw more light on this.
I'm not familiar with GrapheneOS but I assume it follows the usual model when repurposing Android devices of taking various closed source blobs (i.e. drivers etc) and rebuilding the open source bits around them? If so, this approach usually locks you into a Linux kernel version to remain compatible with the blobs which limits you on kernel features and fixes as well as who knows what exposure the blobs have to offer, which also will likely never get updates.