There aren't a lot of downsides to winning games and becoming a good football team. Sundays are more fun, the season goes into January (and February?) and you get to see hometown players doing well.
There's a lot to like.
Of course, the downside is that the players on your team are likely to draw interest from other teams because, as a winning team, they're clearly doing something right. That competition for a player makes it more expensive to keep them when contract time comes around. That's an issue the Chiefs could be facing in the next year (and two).
The Chiefs have a few key critical pieces to their success with contracts coming up.
The current labor situation in the NFL makes these things hard to predict but we'll assume they keep the threshold for free agency at four years. That means the Chiefs could keep Charles and Carr in-house as restricted free agents. DJ? Tamba? The Chiefs can offer them a long-term deal, franchise/transition tag them or let them walk.
If you look at the Patriots over the last decade they've had to make some very difficult personnel decisions. At some point, a player we view as critical -- such as Asante Samuel was with the New England Patriots -- will be traded or will walk because the Chiefs can't sign everyone. The key is knowing who to sign and who to let walk. In addition to that, do you let them walk for free (with a compensatory pick coming back)? Do you trade them? There are a lot of decisions to make and how you make those decisions are critical.
This is a high-class problem for the Chiefs to have and one of the reasons Clark Hunt continually pointed to GM Scott Pioli's drafting abilities. The plan is that, for some of these guys as their contracts come up, the Chiefs have someone in their place ready to replace them.
As they say, it's a process.