Well obvious yo you but I thought there may have been something else apart from the refund. To my mind its not worth it at £165 a year for the convenience of being able to move the van if/when I want to.
I have thought about doing a SORN for mine, but for the same reason as you decided the benefit and flexibility is worth the approx £15 a month. If it were the higher sub 3.5t tax rate, it could have swung the pendulum the other way.
the SORN process is instant, as is the Retax, so someone could SORN their van and later decide to reactivate to use. But a word of caution and something I found back in 2015 (so maybe changed now?) .... if you SORN your vehicle, you cannot retax it on line for a few days. I assume this is because of databases catching up or something.
Due to a tax complication on a van I bought, the only way I could tax it in my name was to SORN to cancel the existing previous owners tax (should be automatic on V5C re-reg but didn't happen for some reason), but then found I could not retax the next day on-line as the "SORNing" was still in process techically, so had to tax at the post office instead.