Doing something consistently over a long period of time has several benefits.
It helps you build mastery in that given pursuit. Whether it is writing daily, training X times per week over a year, or waking up at 6am every morning. The more you do it the better at it you get.
But there is even more utility than just getting better at it.
It builds discipline. It asks you to do the thing even when you don’t feel like it. It challenges you on focus and time management. I think it even builds a bit of grittiness; of committing to the daily grind and doing the work.
The best thing about having a consistent practice is that it gets easier over time. All you need to do is start.