It depends on the look you want. The wood in your pictures looks out of place to me.

The first piece looks like it was pulled from a barn and placed in a nicely finished home with no other rustic elements. Same with the second. The rustic wood does not seem to relate to its surroundings.

Having the wood planed and sanded prior to use would provide a different look, but even then, it may not fit in.

It depends on 3 things: 1. How rough the wood is; 2. What the wood will be used for (ie is there a necessity that it be smooth in certain areas you plan to use it?); and 3. What you want the wood to look like in its "end state".

You can lightly sand the wood (by hand only so as not to over do it) and even use a product like Briwax and a basic burnisher to give the wood a more finished look while also bringing out the texture/depth characteristics of the wood that is so unique with reclaimed materials.

My husband and I used a Briwax-like product on reclaimed wood to make shelves for our kitchen. We had no idea how to do it before that experience and aren't particularly DIY savvy. The wood turned out beautifully.