An alternative is to get a good pad controller. You get a lot out of this beyond just playability (such as knobs — physical knobs are great for experimentation and fast, dynamic changes to things like filters), but it's still something that can be played like a piano in terms of expressiveness. But it's also something that will easily fit on your desk, and the grid layout lends itself to quickly memorizing chord patterns.

I would agree that regardless of the type of music you make (including techno and related genres, which are among my favourites), having a playable instrument will make a big difference to your production. A huge part of this is just happy accidents. The synth part at around 0:40 in this track [1] came about with just pad mashing. A standard part of my process is to record the audio output of whatever noodling I'm doing on a pad controller, pick out the good parts, and loop them. It's way more fun than drawing notes!

[1] https://soundcloud.com/the-track-club/requiem-for-the-voicel...