Don’t let Eurorack-No-Phobia ( on Halloween ) be a barrier. By my measure the base tape module part alone is a good price. The side car unit might make sense, but i’d be inclined to experiment without that. Skip the case.
Not having record heads on this is a bit of a loss but not too bad. I also assume you can’t do a tape loop, though maybe with a capstan you can do a short one which would be fun.
Working out how to record one track as a click track with the module on the output to get a sync would be amazing and doable. You could similarly do a track or more with a gated rhythm.
Take a look at the Jamie Lidell video in this post, where he uses a megabucks custom-built 4 track reel to reel with a CV / MIDI speed control. That in addition has individual erase heads, with record and sound on sound.
But this cassette version gets you a good ways down that path. Having a click track would be possible. Doing the mellotron sorts of things with straight tape, and having the portamento is possible too. Four separate playback heads, means you could have both a major and a minor triad for instance.
Also consider the Finegear Dirt Magnet ( thread ) which is a horse of a whole 'nother color.