Why not these cables for my TT

Looking for cables to use from my Onkyo TX-NR905 to my VPI Aries Scout with a JMW 9 memorial tonearm and an Ortofon 2m Bronze.

Tell me why these won't or will do the job.

#2680 from Monoprice. They are 6ft, 18awg, solid copper, shielded, with 24ct gold plated plugs. Oh and they cost less than $4/cable. Okay with shipping let's say $8/cable.

I am looking at VPI, Audioquest, Anti-Cables, Blue Jeans, and a few others in the $175 - $300 range. But why should I waste my money if the monoprice will do the job?

Has anyone tried them or are using them?
Is there smaller gauge available? 18awg is OK for interconnecs but not for tonearm wire.

The #2680 is a single cable, not a pair for L & R, so you will need 2 of them. Will it do the job? Yes. Does your TT deserve something better? Yes.
After looking at the description and specifications of the cable, I see no reason not to give it a try. You may need a separate ground wire, of course, to prevent hum. Plain old 18 or 20 or 22 gauge hookup wire should be fine for that purpose.

If you decide to go for one of the more expensive cables, be sure to consider the capacitance per unit length of each candidate. As you may realize the tonal balance of MM cartridges is sensitive to load capacitance, and 150 to 300 pf is recommended for the 2M Bronze. That figure applies to the total of phono cable capacitance, turntable wiring capacitance, and phono stage input capacitance. The input capacitance of the NR905 is not specified, but you probably won't be going very wrong if you figure on 50 pf or so. And perhaps a little less than that for the turntable. That would work out well in combination with the 22 pf/ft (total 132 pf) capacitance of the Monoprice cable, but you would want to reassess that total for any other cables you may consider.

-- Al
What you really need to ask is why did you buy a VPI Aries Scout when a Crosley CR6005A Tech Turntable is so much cheaper. when you answer that question then you will have the answer to the other question.
Monoprice has nice cheap cables but for a tonearm app a better cable is a must.
Some of those cables like Blue Jeans, or Anti may not have enough shielding for phono signal use. Good shielding is of course a must for the tiny phono signal.