Interesting when they come out and what they will look like.
There are a few stores in my area that have them. I get why HK would release a general optics ready model with adapter options, like the MOS series of Glocks, but I would still go with getting your slide milled by a smith for a couple reasons.
At least at the stores in my area the 2020 Optics Ready VP9s are about $130 more than the non cut models and then require you to buy a $30 plate for your specific optic separately. Which puts the price of an optics ready model at about the same as buying a non cut VP9 and then having your smith mill it you your optic, so there's no real cost savings that way.
Combining this with the fact that the optic mounting method is bolting your red dot to a plate and then bolting that to a slide, you have more things that can go wrong and a less secure mount than a custom milled slide, the MOS Glocks are a good example of this where while they work, you have issue of screws not being able to get as good of a thread purchase and backing out over time due to the plates not being thick enough for proper depth screw holes, and optics losing zero due to the plate shifting while in use.
I'm sure HK worked on making a good system, but at best it will have performance close to an optic specific cut and they haven't been around long enough to prove that.