In reality, if you know what you are doing, you would never compare like that (0 == "foo"). What would be the use case?
If you on the other hand don't know what you are doing, you are going to shoot yourself in the foot in one way or another.
If you really have some dynamic type situation and you for some legitimate reason don't know if your variable is going to be an int or a string, you would just compare using the === operator, which is a standard and well-known tool and does not have this issue.
I could see this coming up in a pretty straightforward way actually. I used to have a coworker that would always write his conditions backwards, so like
if(false == something) {}
In this case it's a semi-obscure C programming style to avoid accidentally using = in an if statement. (I think it's silly, but a decent number of people do it). So I could easily see a case in PHP where someone writes...
if(0 == $foo)
and $foo usually holds a numerical string, but maybe a user entered "" there and now it's cast to 0 and maybe that code path shouldn't be taken.
Reading data from an excel sheet. A1 is “foo”, A2 is blank. B1 is =A1, which evaluates to “foo”, and B2 is =A2, which evaluates to 0. If you want to aggregate according to column B, you have to compare 0 and “foo”.
You have an excel sheet with various unknown data types which can be a string, a number or a formula that needs evaluation? And you don't check types of variables before comparing them? In that case I would argue that you fall into the category "not know what you are doing", because checking the type would be the first needed thing. That is the very first situation in which it is needed in fact...
If you on the other hand don't know what you are doing, you are going to shoot yourself in the foot in one way or another.
If you really have some dynamic type situation and you for some legitimate reason don't know if your variable is going to be an int or a string, you would just compare using the === operator, which is a standard and well-known tool and does not have this issue.