Feature size prevents computation from being fast, even if you could tweak it to create "organs" that did distributed processing. Basic limits of what cells can do would constrain the clock speed of any particular compute component to ~6khz or less, or about 100x what they can do naturally.

A mycelial mat, coupled to a PCB, with a few genetic tweaks, though, could allow traditional computers to make use of incredible networks that have trillions of intersections; if you could somehow elicit the algorithm underlying human cortical networks, edit fungi to mirror that, you could get a potent AI hybrid device, about the size of a doormat, as thick as a paperback book, but it's not something where a little chip sized chunk of fungi is going to be useful for a wearable. You might do interesting things with robot sensors, if the electrical signaling translates to touch, maybe a thin network of mycelium over a robot could act as robot skin/touch/pressure sensors?

Bravo, science, fun stuff. We're going to get autonomous cyber hybrid mushroom robots, like a "Last of Us" and "Terminator" hybrid.

[from arxiv description] Fungal electronics is a family of living electronic devices made of mycelium bound composites or pure mycelium. Fungal electronic devices are capable of changing their impedance and generating spikes of electrical potential in response to external control parameters. Fungal electronics can be embedded into fungal materials and wearables or used as stand alone sensing and computing devices.

"Computers are useless, they can only give you answers" - Pablo Picasso, via https://github.com/globalcitizen/taoup

I was looking at the fungi in my garden recently and realised there's such a variety of forms, there's no obvious reasons for many of them to exist. Are the fuzzy ones fuzzy because it creates vortices in the air affecting spore distribution? Or is it simply to avoid being eaten by certain types of critters? Are the tiny ones tiny because they are resource-starved, because their strategy is to avoid greater dehumidifying airflow and direct sun exposure above the grass-protected layer, or because they somehow produce greater viability spore distribution and don't need the volume of surface area to do so? Or are they planning to be eaten and have spore travel through digestive tract of slugs? The same question could be asked of huge ones, which are often found with chunks bitten out of them. Then there's some sort of weird fluffy one that occurs on moist ledges where you'd normally only expect bryophytes. Then you've got the slime molds which are sort of proto-fungi that just spam spore everywhere when it rains. All this makes me want to study them or possibly model some of the forms or strategies with biomimicry to better understand them. The main thing I take from all this is: if you have a large plurality of disparate fungi in your garden, it's healthy, because it's a bioindicator of multiple successful strategies in the local micro ecosystem.