I agree about not taking a monitor, but also that it’s useful! I think it is more about having a specific setup that is ergonomic and you can associate with a productive mode.
I’ve travelled on occasion with a hardshell suitcase and a 23" monitor that I’d cut a cm off each corner to squeeze into it. Now I prefer a backpack which no monitor fits in. The suitcase constrains you in your movements (and labels you a holidaymaker!), a backpack is multifunction and worry free. I got a waterproof one with a rolltop that can thus be adjusted in volume. It’s far from essential though, plastic duty free bags are fine
Frankly though you’d be better off with a tablet, you can take it on trips when you don’t want to carry a laptop, and it’s a backup device for when you spill something inappropriate on your laptop. I use my laptop on a stand with separate keyboard for primary, and the tablet (via WiFi or USB) as a secondary monitor for things that the UI lag doesn’t matter too much for—console logs, social media etc.
Adequate savings can be a problem for visas in some countries. Therefore if you want to visit them, the larger the better. Otherwise, not required, all you need is your wits—but as one gets older, savings are preferable, and sometimes when one just isn’t in the mood, so being able to just pay for what you want or need is a relief!
Being digital means you can find better work regardless of ‘where’ you are. Personally I never felt comfortable with less than a few months expenses covered which is the time required to find a traditional job in the worst case. You can increase the longevity of your savings by couchsurfing and such, so whatever amount it is much more flexible that initially appears in the traditional manner. Carry limited cash only, and make sure you have a backup pre-loaded card with enough for a flight in a separate bag. Bank accounts in different countries are useful, especially if freelancing, not to mention that splitting savings between currencies can help protect you against market fluctuations and withdrawal limits/costs.