The safety aspect is more related to the number of hours you have in the preceding month, rather than the preceding year. Don't the AAIB reports always kick off with 28 and 90 day currencies?
If you own an aircraft I can see the motivation to spread the hours thinly over the year, but if you rent you have the freedom to get back current as needed, and then fly a lot for a shorter period. "Getting back current" pretty much obliges you to fly with an FI for a bit, which is no bad thing either.
30 hours/year could be 2.5 hours/month spread out over a year with no feedback on your performance, or 10 hours/month over the summer, after getting checked out.
Same average, different currency, and IMHO different levels of safety.