Activated abilities of artifacts can't be activated.
"He steals power from treasure after treasure, and what does it do for the ouphe? Nothing."
—Jhoira
(14/06/2019)
No abilities of artifacts can be activated, including mana abilities.
(14/06/2019)
Activated abilities contain a colon. They're generally written "Cost: Effect." Some keyword abilities (such as equip) are activated abilities and will have a colon in their reminder text. Triggered abilities (starting with "when," "whenever," or "at") are unaffected.
(14/06/2019)
Collector Ouphe's ability affects only artifacts on the battlefield. Activated abilities that work in other zones (such as cycling) can still be activated.
(14/06/2019)
If you control Collector Ouphe, you can't activate any abilities of your artifacts, even if you'd sacrifice Collector Ouphe as a cost to activate one of those abilities.