The unit of a block size is samples (frames, technically), not seconds. When configuring audio devices for playback you tune both sample rate and block size for latency. It used to be far more common to tune sample rate than block size alone for tracking. This is getting into the weeds of actual devices though.
Also to your point, this is why compliant peak meters use a mandatory 4x upsampling at 48k.
Also to your point, this is why compliant peak meters use a mandatory 4x upsampling at 48k.
This isn't due to latency, it's because the true peak (in the analog waveform) could be between samples.