You'll be hard-pressed to find many wireless mice with an internal battery for less. Several offerings from Fantech for $60 come to mind, but those come without a charging dock. In fact, if we look at mice with charging docks in particular, these typically are only available for more than $100 (Razer Viper Ultimate from 2019: $117 on Amazon currently; ROCCAT Kone XP Air for $129.99). As mentioned in the review, Razer is selling a charging dock (without a mouse) for $69.99 currently. Even MSI's own GM41 Wireless with a charging dock debuted for $94.99, and that was two years ago. A very similar mouse being released for $25 less after two years of steep inflation is not a bad deal in my book.
In short, there aren't many mice going for the same (let alone less) without a charging dock, and factually none with one. Also, keep in mind that the Budget award is supposed to indicate great value, not the lowest price one could possibly think of.
I suspect most people are questioning use of the word "budget" rather than value.
This is a high-end, feature-rich luxury product, being that you pay at least quadruple for the small privilege of having a decent gaming mouse
untethered. So yes, it's a great value, low-latency wireless gaming mouse, but that's like saying that the MSI 4080 Ventus is "budget" because it's one of the cheapest RTX 4080 cards. Nothing about any 4080 is "budget" though.
Realistically if you are a gamer on a tight budget and you're looking for wireless, there are $30 options from big names like Steelseries, Corsair etc, and a whole plague of $15 Chinese knockoffs on Amazon.
I agree with the "great value" review award, but I can also see why everyone is taking issue with the opening sentence to your post "Aimed at budget-minded gamers"; It's not aimed at them - it's a high-quality, feature-rich, high-end mouse costing four times more than you need to spend for a good gaming mouse, and at least twice the cost of several inferior (but perfectly decent) wireless mice you've reviewed in the past.
Edit-
Yeah, having a quick look through your list of reviews, the Steelseries Rival 3 and CM MM311 both seem to be "budget" wireless mice at around half the price of this MSI Clutch. I'm sure there are more decent wireless mice you've reviewed that can be found even cheaper than those two. Honestly though, if I was in the market for a new gaming mouse (wireless or tethered) I'd be tempted by this GM31. It's the shape I like, the charging dock eliminates having to remember to charge it, and the price seems reasonable for the performance and weight, even if I'm not limiting my selection to wireless mice only.