you can use it for piecing if your machine likes it- most piecing is done with 40-50 wt thread's, the brands are numerous and so are we- so if it is the right weight and color for your project use it.
some people use only cotton threads, some use only poly threads, some use what ever fits their need at the moment- i love using silk thread but it's expensive- i hate using cotton thread, it seems to always break every couple inches- but it works well for others so maybe it's just my picky machine-