This card feels very underwhelming in solo. However, it's a MASSIVE defense option for higher count games. The card redirects a villain attack, regardless if your hero is ready and that is absolutely amazing. Imagine this scenario in a 3-player game:
The defending player is first. They can either defend for themselves, or take a hit and hopefully defend for the second player in the round. They can use various ready-effects, some of which conditional and risky, such as Desperate Defense. Now enter "I Can Do This All Day". They can just play it at any time they desire, with full control over redirecting the attack and taking advantage of their DEF, all the while not having to be ready for this to occur. Normally, you could only do this with Preemptive Strike.
The card is zero effort required to take full advantage of your DEF stat. It literally reads "take an attack and reduce the damage by your DEF (which should be at least 3-5 in Protection)". No perfect defense required, player order doesn't matter, just pure defense for those who take the role seriously and buff their stat. A ready effect without the ready effect, for the purposes of defending.
It's an amazing deal for defending heroes in high player count games and probably an insignificant card for those playing solo.