Before you go any further, what exactly are you trying to accomplish here? Are you trying to swap the MX Switches into the Novatouch? It's not going to work how you imagine.
Are you by chance mistaking the switches for keycaps? The benefit of the Novatouch is that you can swap MX Keycaps/Topre Keycaps, but not the physical switches themselves.
Before you go any further, what exactly are you trying to accomplish here? Are you trying to swap the MX Switches into the Novatouch? It's not going to work how you imagine.
Are you by chance mistaking the switches for keycaps? The benefit of the Novatouch is that you can swap MX Keycaps/Topre Keycaps, but not the physical switches themselves.
Yes that's what I had planned.
I see now myself, I seemingly have not properly read the product description.
Apologies for my pointless question
No need to apologize, these things happen. If you end up looking to get rid of one of them, I'm sure it won't be difficult here! 
Thanks 
If it's no problem could you maybe tell me, if there is a significant difference/advantage to using custom keycaps?
I assume there is, since the geekhack forums have their own sub category for it, but it could also just be an enthusiasts thing, to achieve a fully personalized keyboard.
Really sorry if this has already been answered somewhere, but couldn't find anything on the exact reasonings to get custom keycaps right away.
Again, don't worry about it!
Depends on the keycaps really. A lot of it is really personal preference, but there's also the fact that some keycaps will hold up MUCH better over time, some feel better to type on for people depending on what profile they are (more info here:
Keycap Profile Guide)
If you're interested, take a look at these two albums:
Key Legend GuideDoubleshot Keycap Guide (Novatouch is the first picture!)
They provide some good insight into what makes different keycaps better/worse. If you really wanna get in depth, have a look at the wiki here:
https://www.reddit.com/r/MechanicalKeyboards/wiki/keycap_guidesAs for artisans (such as the infamous Bro Caps, ClickClack, etc.), they're purely an aesthetic choice. Some users hate them, others (including myself) love them!