This is too brutal, you have to consider the application domain. For physics simulations I would agree with you. For signal processing or graphics applications float is usually perfectly fine (and even overkill for many DSP applications).

People mentioned the cache efficiency gain with floats, and that is already relevant to rust. If in the future maybe rust could be used for GPGPU, then the difference between float and double often becomes even more dramatic. You definitely want to keep float support for this.