For my angle grinder, I use metal-grinding, metal-cutoff, wire-cup, wire-wheel, and flap-disk attachments. Esp. the first three.
I agree that most bench grinders are underpowered. You press into it a weensy bit and it stops the *^#*@! wheel. I hate that. Anything less than 1 hp won't do. Size 6" is too small (even for home), but 8" is ok. Baldor is high-end, and Delta/Jet/Grizzly seem good. Variable speed is not useful to me. For attachments, I have only a coarse grindstone, fine grindstone, and a wire-wheel. I use the wire-wheel side as often as the grindstone side. Wire wheel is perfect for rust removal, cleaning threads, etc., but then the tool-rest & shield gets in the way so they're taken off. A dressing wheel to square off the grindstone is a good idea. A regular water bucket for cooling hot parts will prevent burning metal. That multitool attachment you pointed out looks spiffy & useful, esp. with the disc/miter-table on the end.
Use a good full-face shield to protect your eyes. Wire wheels also fling off wire strands at high speed (ouch).
And use thick leather gloves. A 16" grindstone removed my knuckle down to bone about 35 yrs ago, and it took 1 second. That finger hurt for many years.
Happy shopping!