In this video you can see a good example of low rate rowing squaring the blade early. Squaring your blade early has some advantages while learning rowing skills and some of those advantages are:
1) It forces you to organize your movements before your catch.
2) It makes the catch easier because there are less things you need to do just before the catch.
3) It forces you to learn to be confident at the catch and have balance by being moving in the middle of the boat and having your body weight on seat and footstretcher and not hands.
4) It helps you to be direct at the catch.
5) It helps to match crews to row together.
This video is really short, only one stroke so you can see it over and make some pause during the stroke so you can understand well how is done.