It's part of the game.
The surface on which the game is played affects the outcome. Natural surfaces are uneven, and they generate uncertainties. Part of the magic of sports, the fun and thrill of being a spectator, is seeing those unforeseen events and how they change the game.
A bouncing ball hits a clump of dirt on the infield and bounces over the second baseman. A linebacker slips in the mud. That's part of sports.
The move to turf, is, frankly, an admission of the surface's role in the game. It simply reflects the belief that the variables created by natural events and natural materials should be excised from, rather than embraced in, athletics. That's a cold, denatured overly controlling view of sport.
Moreover, the visual spectacle of play on a natural surface is superior. Real grass looks better, not in the sense necessarily of being more uniform or more neat, but in the sense that it is what it is supposed to be. A natural surface leaves its mark, visually, on the game: grass stains, mud splatters, even divots, help tell the story of how a game has unfolded as it goes along. Likewise, they communicate to the viewer clues about how the game has unfolded that enhance the viewer's memory and perception of the events. "Wow, look at the grass stain on no. 9 from where he was laid out!" The stain, and the spectator's connection of the stain to the play that generated it, is an additional mental reference point that assists the spectator in understanding and forming a memory of the event.
A turf field is sterile. It never changes. It says nothing about what has happened in the game or how far the game has progressed. It's the last two minutes of the fourth quarter and the game has been fought tooth and nail and remains on the line? The field and the uniforms don't show it. The spectacle is diminished. There is, quite literally, less to see.
Why do we play sports? Why do we watch them? The whole point of human achievement is to strive against an opponent and against the circumstances. The attempt to sterilize, flatten, and control, of which all of this nonsense, from turf to screens, is part and parcel, diminishes the actual endeavor, and a diminished endeavor is less worth watching.