First the stride parameter needs to be a binding parameter. It allows to reusing the same vertex formats but data that is dispatched into various number of buffer. Typically we can expect cases where a vertex format will be used for a perfectly packed buffer which interleave all the data. We can however imagine that the same vertex format can be reused without switching for a data that are stored into two buffers: One static and one dynamically updated.
Originally Posted by Alfonse Reinheart
Second, attribute format conversion is the same cost when done in the shader because it is effectively already done in the shader behind or back. GPUs no longer use dedicated hardware for that, it takes space that can't be reused for something else. That will be more and more the case.