I highly doubt Rand voted against this because of cowardice. Ted Cruz voted in favor so it's not like he would be attacked for it.
Rand voted against it supposedly because it didn't go far enough.
Which is of course a load of bull. He did that because he doesn't want to get attacked in the Republican primary as being "soft on terrorism".
Except that, a) Ted Cruz voted in favor of the bill (did you even read my post?), and b) as I've already pointed out, this bill would extend the Patriot Act's expiration date by several years but would supposedly protect civil liberties by "hiring privacy advocates." That clearly isn't a worthwhile trade-off to anyone who cares more about civil liberties than making it seem like Democrats actually give a sh**t about the government spying on people.
Also, this disingenuous bill was opposed in the House by Justin Amash, so unless you think him and Rand Paul are part of a libertarian conspiracy to support government surveillance, there are clearly principled anti-surveillance reasons for opposing this.