You make FOO.
You also make XXX, which runs on FOO. XXX is very popular.
I make BAR. BAR is very popular, but can't run XXX.
BAR and FOO are competing products.
You say, "FOO is better than BAR because BAR doesn't have XXX."
You don't make a version of XXX that works on BAR.
You can't use the fact that you don't make Office for iOS as a short coming of iOS in advertising. That doesn't make your product better, it just means that you aren't making Office available.
You make FOO. You also make XXX, which runs on FOO. XXX is very popular.
I make BAR. BAR is very popular, but can't run XXX.
BAR and FOO are competing products.
You say, "FOO is better than BAR because BAR doesn't have XXX."
You don't make a version of XXX that works on BAR.
You can't use the fact that you don't make Office for iOS as a short coming of iOS in advertising. That doesn't make your product better, it just means that you aren't making Office available.
Any clearer now?