You do not need to have Digital Voice.
When BT talk about the "landline" they are referring to a "Landline telephone" not the line that delivers the broadband to your property. This is regardless of what type of broadband you have whether it is via copper or fibre and is also regardless of what type of phone you have whether it is Digital Voice or the "normal" phone.
If you decide to drop the "landline" what you are doing is dropping the telephone part of your package. Depending on what type of phone package you have you will save the amount of that call package and you will not be able to make or receive telephone calls. This includes using a Digital Phone.
You could just change your call package to a Pay as you Go package. You will be able to receive calls as well as make them with this package which will cost you £5 per month plus the price of any calls you make. It is free to receive calls.
The cost of the line that delivers the broadband to your property is included in the cost of your broadband package. It can not be done away with and it is not billed separately.
