Storing hydrogen in metal hydrides as described in the article linked to above, post # 71
has been a practice in use since the 1980s.

Turning H2 into hydrocarbons defeats the purpose of using a clean, renewable fuel source, and the cost of the process is far higher than simple electrolysis of water.
There is also the added cost of the carbon footprint incurred in that process.

There are no serious drawbacks in the storage methods you've described, any such are minimal.

The only two serious drawbacks in the whole future of hydrogen power is firstly the mindset of the public, who are largely unaware of the huge potential in hydrogen power, and secondly, the opposition of the petro/gas/diese/oil industry.