I understand you have some problems, solved by using an otg cable.And how did you arrive at this conclusion? As I tried to explain above, within 100m from home point, I can very easily fly without OTG, but beyond that I cannot. So there is definitely something which is affecting the downlink data signal when I am connected to the RC via WiFi and it gets more erratic as the distance increases.
Many users, have the same, or similar stories, also.
But you have to understand, that there are users, who DON'T have these problems.
Also, some otg users report a better experience, but they don't notice any difference with distance, or they say that otg cable doesn't seem to affect their range.
So, seems that otg cable is useful for someone, but not necessary for another.
It depends on the device we use (hardware AND software).
Has nothing to do with how "enough" we have flown our Spark.