Hydrogen electrolysis makes a lot of sense just below the boiling point of water, because you don't need pressure to keep the water liquid, and excess heat from efficiency loss can be recaptured to heat domestic hot water.
If you're prepared to run it at a higher pressure, you can save even more energy because you have less volume of H2 and O2 carrying heat away. But pressure in an electrolyzer makes everything more difficult. What could be plastic now must be ceramic and steel. Pressure vessels are costly and annoying. The bigger they are, the worse they are. If they need to have a removable lid, they're even worse.
Furthermore, the H2 compressor can be placed inside of the vacuum drying chamber so whatever heat it generates will simply assist in the drying process.
