It's better to flush toilet paper down the toilet for sanitary reasons.
Toilet paper is meant to be put into the toilet and flushed down the toilet.
So you should flush toilet paper down the toilet instead of throwing the toilet paper away.
I'm always disgusted when I have relatives over and they throw the toilet paper in the trash can even though I clearly say to them to flush the toilet paper down the toilet.
Toilet paper with poop on it in the trash can is disgusting and unsanitary.
As long as your plumbing is in good shape and you flush the normal amounts of toilet paper down the toilet it should not be a problem.
However if you have bad plumbing then the toilet paper may cause a clog but for modern plumbing and a good toilet the toilet paper should go easily down the toilet and sewer.
Toilet paper is meant to be disposed of by flushing it down the toilet and it's designed to dissolve quickly in the water.
So if possible flush the toilet paper down the toilet instead of throwing it in the trash can.