Not quite the worst use for floats, bad though that would be.
I've received a few SMSes over the pandemic that used a float for their caller ID.
Not sure why the German Federal government chose to identify itself as "+4.4786E+11" when welcoming me into the country (actually me switching my UK SIM card to no-longer-Airplane-mode) and telling me to quarantine and test.
I recently recieved an email from Phillips (re CPAP recall) which said "In the meantime, your device registration confirmation
number is 2.02xxxxE+15." [some digits obscurred by me, although they dropped some of the trailing digits].