The answer depends on your comfort level and the magnification you need.
Most e-readers today let you adjust the font size by pinching in or out on the page while reading. E-readers may not cause eye strains due to their build and the ability to enlarge fonts. So, I think you can read without using reading glasses as long as you’re comfortable.
Some people with bad eye vision say that they have to wear reading glasses even with a big font. So, in some cases, people need reading glasses when reading on e-readers.
Ask me! I own Kindle Paperwhite and always use my reading glasses. Because I feel more comfortable with my glasses instead of frequently pinching them out and in. One of my friends, with average eyesight, can comfortably use e-readers without using reading glasses.
So, this varies from person to person. There is no one answer!
But it doesn’t mean you may not need regular eyesight glasses. Reading glasses just enlarge things you look at, while regular glasses are meant for vision correction so you can see things clearly.