The think is that I will start something that I hope it will become a SME -I know for sure it won't be Internet Scale-, but people tell that using a managed database is a must.
My question is:
Given that I am already proficient with Linux, and my cloud service makes automatic snapshots (besides other rsync backup I do), Is it really such a big deal?
I have 2 projects running a similar setup as yours: everything on a single machine. So far, running since 2014 without any large issues with both of them.
Once, I got locked out of the provider (due to my fault, but it doesn't matter). They've kept the server running, even though I couldn't ssh to the machines. I was ready to redeploy everything on another provider in less than 1 hour, with a DB backup of the day prior of the incident.
If my DB crashes, get corrupts, etc. I have a couple of backup for the last day, week and month, all saved in a different provider.
Thus, in short, I don't think the managed DB really worth for me. I also don't have HA, but I can cope with that. I'd rather get beefier machines for the extra price.
If you lose your database, corrupt it, etc you can't recover and it could destroy your business.
I don't want to deal with that worry so I used managed databases.