Dado, you can use that grinder for HSS lathe tools and brazed carbide tools. Just need the right wheels. You can have a green carbide wheel on one end to shape the brazed carbide and a diamond to final sharpen it. Don't underestimate the efficacy of brazed carbide tools - when shaped properly and sharpened, they are really good tools. For your HSS tools, CBN will work well for you. This type of grinder will allow you to grind all faces of the tool, including the rake angles so it is definitely a keeper.
You are correct. For inserts, you either use a machine like a Accu-finish to sharpen them or dump the insert when dull.
My opinion is to sell it. These carbide grinders that MSC, Jet, and the other Chinese grinders sold on well known tool web sites are junk unless you rework them, starting with taking them apart, and turning them in a lathe between centers to get the spindles to run true. There's Youtube videos of how to do it. If you put a decent Diamond Wheel on them out the box you can pretty much kiss your money goodbye. Also, unless you can mount a brake on the spindle, you'll be sitting there for an hour waiting for it to slow down enough so you can reverse the wheel to grind the opposite angles on your tools. They're getting $250-$300 for a good Baldor carbide grinder on Craigslist, so do yourself a favor, and if you don't need this one, dump it and get a good one when you do. And by the way, you will destroy that wheel grinding HSS, and it's not a cheap diamond, so take it off that grinder and keep it for your new one.