The author doesn't make much distinction between Single-Level Cell (SLC) and Multi-Level Cell (MLC) SSD drives. Of which, the MLC drives are cheaper than SLC drives but sacrifice some performance in the process. All the drives listed here are MLC drives (since there was a price cap) and we would see better performances out of their more expensive SLC counterparts.
I'm waiting for the and which leads to your point...
In past reviews where SLC was an option we discussed the merits of it, we have even reviewed a few SLC based SSDs.
https://www.techspot.com/review/201-ocz-agility-60gb-slc-ssd/
As you said there was a pricing cap on this article and anyone on a budget that wants to get a taste for what SSD technology is about is not going to worry about anything using SLC memory as the cost is astronomical.