They're the first cards experienced players think of when they want their green deck to draw a lot of cards
Liliana Vess allows the player to force their opponent to discard cards, allows them to search their library for a specific card, and can return all creatures in both player's graveyards to the battlefield under their control, flooding the board with creatures for a huge swing, which will often lead to the end of the game
If your main goal is to make Legacy more affordable and accessible, however, there are other, better, easier ways to do it that dont involve fighting against WotCs seemingly unbreakable oath
Reducing all your opponents hand limits by one isnt the strongest ability, but its a fun and original way to annoy your opponents and give them some disadvantages
If you want, you can open your two daily packs to complete your daily missions
That delay buys you time to swing or stabilize, making it especially nasty against token swarms