It seems to be to do with activities which require you to take aim.

My husband is right handed in everything except cricket and golf, which he plays left handed. I was curious so did some research to see what this phenomenom is known as.

It's CROSS-DOMINANCE

"Cross-dominance, also known as mixed-handedness, mixed dominance, or hand-confusion, is a motor skill manifestation where a person favors one hand for some tasks and the other hand for others. For example, a cross-dominant person might write with the left hand but grab primarily with the right. Ambidexterity is a well-known variant of cross-dominance, but cross-dominant people may also be left or right-handed rather than ambidextrous.

It can also refer to mixed laterality, which refers to a person favoring eyes, ears, feet, or hands on one side of the body. A person who is Cross-dominant can also be stronger on the opposite side of the body that they favor; for example, a right-handed person can be stronger on the left side. Cross-dominance can often be a problem when shooting or in activities that require aim".

So, there you go! I suppose you 'aim' at a key when you text on your phone, but you don't have to 'take aim' when you use your mouse. Same as my hub has to take aim when he addresses a cricket or golf ball, but not when he writes.

:D