Actually you don't need reading glasses as you can see fine when reading. People only need reading glasses when they have presbyopia. But varifocal glasses may give you more comfortable vision for reading if you have different prescription between the two eyes.
I can't see any reason why you need varifocal glasses as you can see fine when reading. Also varifocal glasses are quite difficult to get used to and I don't like them any more. If you are happy with your single vision glasses, you don't need varifocal glasses.
Varifocals allow you to read and see in the distance at the same time. However, if you have no problem when you do some reading, then there is no need to get varifocals. You can take your current glasses off when you start to do the reading.