if expression and match expression

Code first:
 

 let rec has_element1 l e =
match l with
| [] -> false
| h::t -> if e = h then true else false
;;

let rec has_element2 l e =
match l with
| [] -> false
| h::t -> match h with
          | e -> true
      | _ -> has_element2 (List.tl l) e
;;

 

 has_element1 works as I expected. 

 And I rewrite has_element1 with replacing 'if expressing' with 'match. 

 But has_element2 always return 'true' and it gives me warning: 'Warning 11: this match case is unused'
 

 Questions: 

 (1) Why does my has_element2 always return true? Match expression I used in has_element2 not the same as if expression in has_element1?

 

 (2) If I have an option; if expression vs match expression. which is better (in general) ?