So, I went to my collection and looked at various cartridges from various systems, as a comment was made about there being specifications for card edges on cartridges (which I have never seen for cartridges of that era, although PC Engine HuCards definitely would have had one - but since NEC manufactured the HuCards on behalf of everybody, they didn't need to publish a standard).
Famicom: I can't see any bevel on any cartridges I have, although I do see a minor edge indent on one side, consistent with a PC Board "V-cut" (which I also see on the MegaSD).
Genesis: bevels, non-bevels, things are completely non-standard. The ones which are bevelled never come to a point (as a PCI bus card would), but rather a flat edge about half the thickness of the board.
Super Famicom: slight bevel on all; more than a V-cut, but the card edge is flat for about half of the thickness of the board.
PC Engine: everything is bevelled, significantly - and edge-smoothed. But this stands to reason (as explained below).
Most computer board edges had very little if any bevelling in the early days (i.e. prior to 1986); the bevelling seemed to be introduced when greater pressure was applied to the card edge by the connector, also for single-edge connectors (as there is reduced play if only one side contacts), and especially as pin width decreased (as the pins became significantly more fragile). This is evident on the PCI card bus (circa 1989) - the first time I saw a card-edge bevel standard published, and the PC Engine's HuCard edge (which I have personally seen jammed pins on, multiple times).
But for the wide-pinned Famicom, this wasn't originally expected to be a problem - although it may well have become one during the Famicom's life, as seen in the slight bevelling of Super Famicom games, and some Genesis/Megadrive games.
On the other hand, I did see one relatively significant variance between most Genesis games and the MegaSD: the PC Board thickness for the MegaSD seems thicker (and my callipers measure it to be 1.6mm as opposed to 1.5mm for other carts). While there is probably enough play in the double-sided card edge for standard thickness, this extra thickness would definitely benefit from some bevelling.
If you could supply a reference to a manufacturing specification for Megadrive/Genesis carts where bevelling amount is specified, I'd like to review.
In the meantime, I just broke out the sandpaper and bevelled the edge of my MegaSD slightly in the past 5 minutes. I aimed for a 45-degree angle and for the leading edge to be no thicker than about 1mm. 180 grit worked fine. And unless you're in a super-low humidity location (where static build-up might be a possibility), you shouldn't need to worry about damaging the cart.
Oh, and rather than ask whether a card bevel is a "flaw" covered under the product warranty (as this is likely by design), you should instead be asking whether damage caused by a lack of bevel is covered. Jammed pins could *potentially* be caused by this, but I have never heard of such a report on wide-pinned systems.
(And while this post is as honest, factual, and fair to both sides as I can be... I expect that I have pleased exactly nobody by posting it.)