The reason people use keycap pullers is they put a more even force on the cap when lifting it off. Yes you can come up with your own way, but try to lift them straight off, vs rocking them, which can loosen the fit or even break them.
That said, the wire type keycap pullers will not work on the spacebar, which is why they give the disclaimer to remove surrounding caps first then pull it off by hand, or use a plastic puller. Plastic pullers are OK, but less durable.