Same as the difference between the 100M dash vs. the Marathon.
Different breed of skills and athleticism. One you pace yourself and strategize accordingly, the other you have to go all out from the get go.
Fewer room for mistakes in one and in the other you have time to recover.
One brings in the excitement, the crowd, the money and the other satisfies the critics. Its like music, you have your bands/groups/artists that have hit songs because they are fun and enjoyable to listen to but critics feel the lyrics and music must have meaning for it to be considered a good song.
One allows more cricket to be played, less fatigue on the players, more professional options for players while the other is a dinosaur which is an amazing part of history but has no business in today's world.
Welcome to wherever you are, this is your life, you've made it this far...