Nothing wrong with auto start/stop by itself, just let the driver turn it on and off, and remember the state between drive cycles.

It comes in handy in some situations while being a nuisance in others, and that's when you add a button.

ANL offered the following guidance in 2015:

  - Limit engine start cycles to approximately 10 total cycles per day, on average. Occasionally cycling the starter system more than this will not cause damage unless it becomes a long-term trend.
  - Assuming seven additional cycles per day are not exceeded (assumed ten total cycles per day), any shutdown with a duration in excess of one minute will result in overall cost savings.
  - Limit electric accessory use during shutdowns, particularly during longer shutdown periods.
  - Drive more than five miles between start cycles to ensure the battery is fully charged.

(https://publications.anl.gov/anlpubs/2015/05/115925.pdf)