Sometimes it is not about savings.

Inverter felt more comfortable because your room temperature won't surge and fall, Inverter provided constant stable temperature with minimal surge or drop of temperature due to the compressor will be able to adjust to its need VS Non-Inverter would either go 100% max or turn off 0% when it reaches desired temperature.

And another misconception.. A/C performance being cold or not is not measured by being inverter or not, look at the spec sheet,
BTU is the one you need to look for to match with your room size.

Inverter A/C is a very mature market, the durability of the product also highly dependent on user and their maintenance as well.

if you are not cleaning A/C often with the right way, many thing can fail prematurely, this including using those sketchy A/C service that spray corrosive chemical to your parts for cleaning or claim deep cleaning while they only spray chemical on cooling coil.

Those a/c guy advise just take it as a pinch of salt lah, I don't think inverter is that fragile personally and it highly depending on the environment where it is being place and its maintenance like u said those good for nothing self proclaim expert spraying corrosive stuff sure can deep clean and even remove important material.

Personally I think if your piping all ready for Inverter just go ahead, but if your existing piping only made for non-inverter, then better to stick to non-inverter otherwise u need to spend a lot to revamp what's concealed in the wall.

Again... i my opinion Inverter is not just for saving, it is the comfort it provides without fluctuating temperature, the savings are just something extra that came along with it.