A lot of guys got started on those benchtop round column mills, and they're certainly better than nothing, but I'm not sure I'd buy one brand new. If I were wanting to spend the money on a new in box bench top, I'd at the very least want a square column, and I do agree that a DRO is VERY useful, and yes, probably even necessary. I bought a used knee mill that did not have a DRO, and I got by for a year or so without it, but when I did finally get one slapped on, it basically became a brand new (and much more capable) machine for me. I could't imagine not having a DRO now, and you can get some very capable Chinese DROs for less than $100 per axis, which is a no brainer, IMO.
For any mill you buy from HF (and even Grizzly), you should plan on needing to make some adjustments right out of the crate. I'm not sure if things have improved over the years, but it used to be that the HF mills needed disassembled, deburred and possibly even scraped, and some of the more fragile parts would benefit from upgrades. Precision Matthews used to offer some different upgraded versions of the Grizzly G704 mill, though I'm not sure what they have now. They used to come with better motors, and tighter tolerances out of the box, IIRC, though you do pay a little more.
I'd still encourage you to consider a used knee mill if you can find a reasonable deal on one. You can do small work on a bigger machine, but you can't do big work on a bench top machine. A bigger machine will hold much tighter tolerances due to its mass, and it will work faster and take larger tooling as well. I have a full sized knee mill, and there are times that I still wish it were bigger.
Another benefit is that you can put multiple vises, jigs, and work holding setups on the same table if you're batching a lot of smaller work, where you don't need a lot of x travel per part.
Again, if it comes down to getting a mini mill or nothing at all, I'd take the mini for sure, but if you're like most of us, you'll very quickly out grow it, and be looking for a used bridgeport within a year.