For myself, I use to play without a mouse pad. My table was decent and smooth. I just had to clean it every so often in casse of dust build ups or the surface becomes uneven.
Recently I started playing on a cheaper table that screws up my mouse sensors, so I was forced to get a mousepad. Playing on a mousepad was pretty much the same as playing on the smooth table except I don't have to worry about weird bumps and stuff like that.
In the end, playing on a mousepad isn't needed imo if you have a simple smooth table, but if you need one, I recommend you get a mousepad of a relatively large size (one that doesn't restrict your movement) that lasts for a while (if the mousepad starts having the cloth roll upward in a month, you have problems)