An oscilloscope is not necessary for someone who is starting learning electronics. It is an expensive and complicate piece of kit, and can actually make learning harder if you try to use it early, without first having developed both an "intuitive" sense of what is going inside a circuit, and the practical knowledge needed to properly use it.

But as you do develop this knowledge and skill, an oscilloscope is definitely very useful. Just to be able to see a signal as it changes over time, and to probe it by zooming in and out, changing the time scale, decoding communications, will really boost your understanding.