Your 2004 Prius did not have that. Are you saying it was unsafe? Most cars in the road do not have this feature, including my 2017 Prius. Does that automatically make my car unsafe??
It's a safety issue because the Prime doesn't have a spare. I need to be able to see a tire start going down, not once it's already low, so that I can stop and deal with it as soon as possible. On a long trip off the beaten path, this can matter.
Yes it would be nice to see if one tire was on the low side compared to the others (and on what corner) like we can with the 09 Lexus RX450h. Or at least be able to view them with a scan tool.