Hockey skates have blades which are rounded at the front and the back. They are designed for the sudden stops and quick turns that are necessary in the game of ice hockey.
There are a great range of hockey skates available today , from low cost entry level ones to top competition skates at a very high price. The differences lie in their build quality and strength. Entry level boots are generally not usually suitable for playing hockey as the softness of the boot doesn't offer any protection to the foot if it gets hit by a fast moving puck.
Blades on entry level boots are fused into the frame and so they are not replaceable, These boots are intended for recreational use only and if that is all you intend to do, then there is no point spending a lot of money on boots that were built to withstand full on Hockey.
Moving up the levels, you'll find the boots get far more rigid, and blades become replaceable. With these boots, if a blade gets broken during a game, it can be swapped out relatively easily and the player can play on.
At the top levels, the strength has been increased to the maximum, but the boots will still be light in weight.