I had a really nice heavy old school 8" pedestal bench grinder. I had a minor accident with it. Sometime later, a fellow blacksmith was killed by his. I immediately sold mine on Craigslist for cheap. The fellow who bought it said it was funny. The factory he worked in got rid of all their wheel grinders and replaced them with belt grinders. This was enough for me. I still have a small bench grinder, but it is old fashioned and it runs slowly. I would like to look into one of those slow-speed grinders. If I want fast, there's the angle grinder.
Looking at the various YouTube videos, there is a definite grouping of tool grinding fashions. The "slow-speed" genre seems to be using types that have one wheel right-angle drive, geared down, often originally with a wet wheel, as for sharpening woodwork tools. Leaving out the water, and mounting a low-cost diamond-coated thin metal against a MDF wheel, and setting up angle rests to grind tools on the flat(ish) face is another way.
I see a whole bunch of videos that use geared down drive and a cup wheel which has diamond impregnated resin around the rim. They vary from about 2" to 6". The result is a flat grind, and is apparently for carbide tools. Various projects go for the 12V or 24V DC motor worm drive.
Belt grinders is what I have not tried (yet). Working like a linisher, but with a long belt around a route of bearing rollers with a slight convex profile to keep the belt running centred, they are popular, especially the 2 x 72. Welding up one's own version of these seems to be a popular project. Folk also purchase these, and set about a series of "functional improvements" especially for guiding and setting angles.
The notion that grinding wheels are so dangerous one should trash them altogether is, I think, countered by the fact they have done useful work for centuries, and in the modern machine shop sense since the mid 1800's. I find it a bit disturbing the notion that maybe the wheel quality is going down, such that there are unbalanced mass regions internally. (Ref
@Janderso #13).
Can it be true that the wheel uniformity and quality from brands like (say) Norton and others is now not what it used to be? Is it now only to be CBN (Cubic Boron Nitride) or PCD (Poly-Crystalline Diamond) in various resin bonds? They may be great, but to quickly carve away tool steel or carbide to a shape does seem quite well done by a aluminium oxide or silicon carbide wheel. They do very well on surface grinders also.