SanDisk claims some of their cards draw higher idle current in SPI mode if the unused pins are not pulled high. I have not seen this on new cards. I ground unused pins and maybe all that is important is they are not floating.
The ‘RSV’ pins are floating inputs. It is the responsibility of the host designer to connect external pullup resistors
to those lines. Otherwise non-expected high current consumption may occur due to the floating inputs.
Newer cards seem to have two levels of sleep. When idle for a second or two, they draw 200-500 micro-amps. They then drop to 50-80 micro-amps. I should do some tests to see how long it take for them to wake from each mode.