This discussion regarding a sportsbook option to their casino is discussed on many threads here and actually I like the option but for the dev side there are so many things they need to look for since they need to see if many in game user really want this to happen, but if their players are still in good shape with their current games offered then better they should tick with it for a while and plan for better promotion which their player feel excite to participate in their events.
They do not need that much dev time for it to happen. Obviously I am not saying it is a kids play, for example I do not know coding that well, I know just a bit of front end (and obviously wordpress but that is not coding if you ask me) and I know what is required, I can't do it even if I was paid to work on it for a whole year, not because it is impossible to do but because that is not my job and I would fail at it and wouldn't even know where to begin, first I would have to learn it.
However if you have developers who built chips.gg that means you have great developers, it is a very difficult thing to build chips.gg and whoever made it is an amazing developer. Which brings the question ; most sportsbooks are provided by some third party, you just take the odds, automate it and put on your own outfit to it and publish it as your sportsbook, I am sure that must be not "that" difficult, at least sounds easier than building the whole chips.gg from scratch.