Like most things, isn't there a balance to be had.
Small children do need the loo often and need to use the potty. Parents of small children need to remember that just because they are living in the small child zone, not everyone else wants to nor should be forced to see and put up with toddlers on potties, toddlers screaming in restaurants in the evening, toddlers in the flower beds.
My current experience is that often parents of toddlers become so wrapped up in their kids, that they forget about other people and feel entitled to do whatever they like with little or no regard for others....they often have a huge sense of entitlement to continue their own life with little or no thought for the impact it has on others....as if the needs and wants if mall children and their parents trump all others.
Of course, it is possible to use a potty without it being in the middle of the pavement. Of course it is possible to go out for the day without allowing a toddler to run round a cafe and shout, spoiling the enjoyment of others, of course it is possible to have a day out, without the toddler needing to get in water fountains or flowerbeds.
Potties can be used in cars, in deserted areas, at the edge of the pavement if needed, behind bushes. Sometimes, it might be that they are used and create a bit of mess for a parent in the car....and many parents will choose to inconvenience themselves like this, rather than to inconvenience and upset others by the potty being in the middle of the path or the middle of the supermarket aisle because.....they understand that it's their child and so the inconvenience should be to themselves and not to every other passerby. The problem is when parents decide everyone else should be inconvenienced because being a parent with a toddler trumps everyone else and the parent and child should always have exactly their own way.
Rant over...almost.
So, use the potty when needed. But engage brain and consider others too. Try to put others first and be prepared to inconvenience yourself sometimes, rather than letting your children inconvenience others.