It's important to be aware that this perk does not cover sets like MH2, MH3, and similar ones
I also appreciate Migratory Route and Sanctum Plowbeast for their mana-fixing even though I'd never want to cast them
The benefit of Glider is that it can be attached to other creatures later in the game in order to provide them with a power and toughness boost as well as evasion in the form of flying
Thanks to our ramp spells (Paradise Druid and Growth Spiral), we can often get Narset on the battlefield on Turn 3, making it fast enough to help stabilize the board against creature decks, buying us the time we need to start casting Ultimatums to take over the game
For instance, another Commander addition to Legacy, True-Name Nemesis is difficult to interact with
If you want one for your collection as an historical trinket, I recommend reaching out to Keith Adams on facebook or similar and he can probably hook you up