Whether it's a good move or not is highly dependent upon the game. There's quite a few games (or gaming platforms) that will almost never go on sale, or their sales are a very minor discount. The reason behind this is that the games and/or IPs are strong enough that you don't need to put them on sale. If your game is weak and/or not moving well, you'll tend to see them go on sale more frequently and/or for deeper discounts. While the trends slightly change for events and sales that are independent of an individual game, the general trend still applies.
This trend is easily seen on Steam. Games that sell really well or are popular at launch tend to not go on a sale at all for a very long time (almost a year in some cases), and when they do go on sale it's usually in the range of 10% to maybe 34%. However, there's been a bunch of AAA games that have had bad launches or are not well received that will go on sale between 34% to 50% within a month or two of their launch dates. What's the reasoning behind this? If a game is good or popular, you don't need for it to go on sale until you reach a saturation point of customers... at which point, you can afford to put the game on sale for events or promotions as you've likely tapped most of the potential people who will buy the game at your price point. It's not like you really have to worry much about clearing inventory for games anymore as things tend towards digital nowadays, so the reasons for putting your game on sale are more directly related to how well the game is selling and performing overall.
To put it mildly, the reason Dragonflight keeps going on sale is because it needs to be on sale. Yes, you can strategically place sales to boost purchases, but the frequency and magnitude of the sales are indicating that Dragonflight is having sales and participation issues. If Dragonflight was selling well and had good participation rates, the game would go on sale less frequently, probably only going on sale for 10% to 25% at this stage of the game. While I could tie this into WoW token and services sales with respect to how they could potentially indicate why the sales are happening, that's a really long post I don't want to make.