I asked myself this question to myself two years ago.Now, I would say that Separation is very much needed because the initial meeting is very strong and your Twin Flame encounter hits you hard.
To release the intensity, Separation is ideal just to absorb, comprehend and choose to accept what is happening to you.
Naturally, physical separation is negative but to the soul, it is an opportunity to grow.
The love never fades; Separation only proves that what you are experiencing is alien, and real but beautiful.
Separation is only there to test you at how much faith you have in your Twin Flame Process.
I hope this simple read can be very helpful to you.
Thanks for the question.