I wouldn’t buy a series 3 today, it barely keep up with itself now, and sometimes has issues even with updating the OS because the onboard memory is small/limited.
The SE is a much better deal in terms of longevity of using it, and as it also has a bigger screen for the same size watch.
The Series 3 has a much slower CPU. As in slower than it needs to be run the UI. The "SE" is a Series 5 (CPU wise) and much better value.
If you're not expecting the giftee to interact with it very much (i.e. just use notifications and Apple Pay) it might be ok.
New Apple stuff is rarely sold for less than RRP.