Even if you only have stitches you want the ER to have those machines just in case the doctor looks at your injury and says "wait, this isn't the standard routine thing everybody has we need to get you into the expensive machines". Probably this will never happen - the doctor will always look and see the standard routine things that everybody has and you don't need the rest.

This is why urgent care exists and is why if you don't have something that you think is life threatening, that's almost always better. If you need more than they can provide, they can and very much will forward you on to an ER