Some of us do that, but I try to find a balance between casual and competitive
Senu's last ability will trigger only if Senu is already exiled at the point immediately after blockers are declared and at least one legendary creature you control that attacked isn't blocked
The quote above describing the themes of the deck mentions making attacking you difficult, and there are some great reprints that do exactly that: Ghostly Prison, Propaganda, Windborn Muse, Sphere of Safety, and Kazuul, Tyrant of the Cliffs
It's one of many 'edict creatures' that force players to sacrifice something when they enter the battlefield, and it might be the best version ever printed
Also, practice so you don't miss your triggers in the future
Now, imagine if you already had Rosie Cotton of South Lane in playthis combination would be powerful and potentially very problematic for your opponents