Common Button cells have low capacity when compared with AA/AAA cells.
From 30mAh up to 300mAh for common cells.
AAA long life rechargeables Eneloop started at 800mAh or 2000mAh for AA. Long life single use Alkaline batteries have even greater capacity.
The trade off is that for very low use items EG bathroom scales, the extra capacity of a AAA may not be needed.
We have a button battery for our kitchen scales (a model recommended by Choice) sitting on top of the scales as it drains all the power even when not in use if the battery is left in. Luckily there aren’t any kids around.
This must be one of the dumbest ideas this species ever came up with. Not only is it generating waste of single use (unsafe) button batteries but it is generating waste of single use electronics. 
Regarding safety, if you do the right thing and put all these button batteries aside pending the next eWaste collection / dump then that is another place that little fingers can get their hands on the batteries.
Safety solution for this particular application: ditch the entire idea! If people need reminders every 12 months to replace the filter then that reminder can be sent via text / email / whatever.
Hi did you watch abc tonight about those batteries the ladies of kids who died contact target and overseas supply.
I purchased a pair of vernier calliper with button battery from bunnings i forgot the brand. It is very easy to open and take battery out. Any child would swallow it.
I recently struggled to defeat the packaging for a replacement button battery for the Toyota key fob. Evidence of one of the changes delivered.
It highlights that there are many legacy products still in use that depend on button cells. In the example of the Toyota key fob, it needs two ultra fine screws to be removed to get to the battery. Hence secure.
Risk remains until any used button battery is safety disposed of.
We had some elderly parents stay with us where one wore hearing aids. On vacuuming the house after their departure we got some pings (two of them) up the hose. As we often vacuum up lego/meccano/vex, we decided to check out what the noise was, just in case is was lego etc. In the dust collector were two very small button batteries from hearing aids.
Fortunately our child is past the age of picking up things off the floor and sticking them in the mouth, but this did highlight how easy and accidentally a dropped button battery could become a life threatening problem.
