The section just in front of the frontmost big hole is where the jacking point is constructed..... I would suggest that the amount of rust visible in that area would warrant further investigation.
The jacking point is basically a metal box, with one face being made from the sill plate, but the rest hidden from view. I managed to remove mine and weld up a replacement quite easily as the bits you can't see had dissolved sufficiently on mine to make it not fit for purpose.
Whilst you're there, it is better to have a look than to find that it is bad at some time in the future when you need a wheel change and the jack goes through the sill into the footwell.
Personally, I'd cut and replace the rusty bits (easy for me to say when I have a big garage and a welder!), but if you need to just 'kill' the rust, any Phosphoric Acid based rust converter will do......
Halfords do a selection, or easily available from Amazon etc
https://www.amazon.co.uk/Hammerite-5092 ... th=1&psc=1