Even if you never have a landline, you might want to use that wire again. I have repurposed old phone wiring for many things = thermostats, alarms, doorbells, etc.
If you really don't like looking at it, you could clip it off just above the staple above the baseboard. If you ever need to re-use it, there's enough to work with.
I would terminate the cable in a screw terminal surface mount jack on the baseboard.
These jacks are very inexpensive, readily available, and can be installed in just a few minutes without any special tools. If someone ever wants to repurpose it, they can use the jack or extend from it by splicing on the screw terminals.
This way if you or someone else in the future ever wants to use that wire, you can easily splice on at the screw terminals and extend the line where ever you want.