Depends on the age of the house. If your house was built when picture rails were standard and built in from new, very broadly, any property built before 1940 then leave them. Taking them out may affect the value of the property. In older properties, people now look for original features and mark those without them down.
If the picture rails were retrofit in a postWW2 property, then it might be a good idea. Builders stopped fitting picture rails when they reduced ceiling heights to make houses cheaper to build
Our last home was big Victorian semi and it sold quickly and well because it had all the original features. We never told anyone that they were all fairly new - the people who owned the house before us had 'modernised' the house by removing picture rails, coving, ceiling centres and some of the fireplaces. We put them all back in!