Plumber Suit Controversy

From Ben10versepedia

In the episode "Ultimate Weapon" Maxwell Tennyson wears his Plumber Suit to aid in his and his grandchildren's pursuing of the Sword of Ekchua. He claims this is because the sword holds the fate of humanity.

If this is true then why wouldn't he do the same when in the episode "The Big Tick" a giant alien tick was threatening to absorb all of the nutrients of the planet blowing it up in the process. Wouldn't this actually be an even greater risk.

Or why wouldn't he do this in the episode "Camp Fear" when the Fungal Brain was threatening to release spores, which would take over the planet. Wouldn't this also be a greater risk.

Why would he be much more concerned enough to use the Plumber Suit for the sword than giant alien creatures.