Are you confusing CRF with CBR?

CRF is the video equivalent of VBR music. The music equivalent of two-pass video encoding is ABR music.

When tuned for a specific file, CRF and two-pass video will give similar results. They both result in a variable bitrate encoding.

When using the same config on different files, you might find that two-pass encoding produces unnecessarily large files for something with little movement like anime, or has quality issues for something with a lot of movement like a lot of shaky camera or film grain. Meanwhile the same CRF setting will work well in just about any scenario, using more bitrate for files that need it, and less bitrate for files that don’t.

2 pass encoding is only to get the benefits of variable bit rate when targeting a specific file size. If you don’t have a specific file size in mind, that’s what CRF is for.