Adapter voltage different to both mains power and appliance expectations

While a lot of people will say this is probably fine — and it probably is fine — I would definitely not do it myself, because given the difference between "probably" and "definitely" here could in the worst case be as dramatic as setting fire to the building or getting a bad electric shock.

Travel adaptors are often dodgy enough as it is, especially the cheap Chinese ones. They're also cheap enough that you can get a correct one without much expense or hassle. As others have stated, there are a multitude of reasons why the adaptor might be rated thus — maybe it uses really cheap terrible insulation that is just about OK for ~120V but not for ~230V. Maybe it's just not been tested at 230V but it'll probably work. Maybe there are other components like a circuit to power an LED that will blow out and make the adaptor useless at 230V. Maybe it'll be fine. Maybe it'll start arcing and burn through the plastic. Unless you are the manufacturer, you just don't know why they put that rating on it.

My opinion is that at mains voltages, there's no reason not to put in a little extra time and money to better ensure your own safety and the safety of others. While it will probably work without issue, I wouldn't count on it myself. I've seen some truly badly-designed travel adaptors cause all sorts of potentially dangerous trouble in my short time at university among people with foreign electronic devices — and those were adaptors being used for their intended purpose, they just happened to be really terrible and non-standards-compliant. There's no reason to add additional risk on top of this.

First of all, let me welcome you to The Philippines (in advance).

One thing is for sure, you can't use 120v adapters here. 200-240v is fine, I've used it before as I shop from international sellers.

Sockets here usually have the 2 straight line hole (i'm not sure what thats called).

I've mistakenly plugged appliances like radios bought from the US here before and as soon as I turn it on it just goes in smoke.

But you can always buy the adapters once you get here. Places like AceHardware should have them.

As for phone and laptop chargers I always noticed that they are rated 100-240v so you might want to check your adapters rating first. Those should be fine.

I have burned out a 110V marked Oral B toothbrush charger by plugging it into 230V instead.

I have also burned out a dual voltage travel kettle by forgetting to flip the switch. Yeah, I am good at destroying my stuff. What's common in both? It's not an adapter with high voltage coming out , low voltage going out. I would say this is your rule of thumb: if there is a plug hanging out on the low voltage DC end to charge your phone, laptop, tablet, travel DVD player or similar electronics you are good. If it contains a coil then you are not.