You'll have specify exactly WHICH modules you're thinking about acquiring. You'll also have to build-out an entire system from scratch around them if you choose to start your first case with them. Why are they a good decision for you specifically? That's a rhetorical question only you can answer. What are you looking to accomplish and what external gear will your Eurorack case be interfacing with?

Those ACL and Waldorf might be better purchased later on... depending on the modules. Maybe not. It's all going to come down to your needs and what the SPECIFIC modules you want can do for you. A lot of what you get out of a module is determined to what other module(s) it's connected to... so take Youtube videos with a grain of salt. Here are some results you CAN achieve with all the modules that are patched. Take away one of those modules and you might have a completely different sound.