PostgreSQL NOT NULL foreign key and default value with sequence

I'm analyzing a following PostgreSQL schema:

CREATE SEQUENCE ref_email_type_ref_email_type_id_seq
  INCREMENT 1
  MINVALUE 1
  MAXVALUE 9223372036854775807
  START 1
  CACHE 1;

CREATE TABLE ref_email_type
(
  ref_email_type_id integer NOT NULL DEFAULT nextval('ref_email_type_ref_email_type_id_seq'::regclass),
  description character varying(50) NOT NULL,
  CONSTRAINT ref_email_type_pkey PRIMARY KEY (ref_email_type_id)
)

CREATE TABLE email
(
  email_id integer NOT NULL DEFAULT nextval('email_email_id_seq'::regclass),
  ref_email_type_id integer NOT NULL DEFAULT nextval('email_ref_email_type_id_seq'::regclass),
  email_address character varying(100),
  CONSTRAINT email_pkey PRIMARY KEY (email_id),
  CONSTRAINT email_ref_email_type_id_fkey FOREIGN KEY (ref_email_type_id)
      REFERENCES ref_email_type (ref_email_type_id) MATCH SIMPLE
      ON UPDATE NO ACTION ON DELETE NO ACTION
)

Does it make any sense to have email.ref_email_type_id declared with DEFAULT nextval('email_ref_email_type_id_seq'::regclass) in case of NOT NULL and existing constraint:

  CONSTRAINT email_ref_email_type_id_fkey FOREIGN KEY (ref_email_type_id)
      REFERENCES ref_email_type (ref_email_type_id) MATCH SIMPLE
      ON UPDATE NO ACTION ON DELETE NO ACTION