Beginning harp music does not modulate much so some lever harps are designed to make the transition to pedal harp easy – no point paying for pedals when you aren’t going to be using them. Also you can get started on one more cheaply while you take your time to think about this! There is some fine classical music being written for lever harp (Bernard Andres for instance) and many arrangements, but the older classical repertoire was mostly intended for pedals.
The harp can be very ergonomic, if you put enough attention into working it out and have the right teacher to help you. I play with mine tilted only just beyond the balance point so there isn’t much weight on me and it is on both knees – my shoulder is completely free and I can lean back to play the top notes. Blisters on the finger tips can be a problem but if you stop practicing when you feel them beginning they can be avoided.