Well, now I'd say S10 lite is totally worth it over a71. A71 is about 400 now compared to £480 for S10 lite, and for that extra £80 you get:
Much better processor (sd855 compared to 730), good for future proofing.
Same amount of updates but better ones (e.g.more features included like one UI 2.1; a71 won't get this)
8gb Vs 6gb ram
MUCH better camera; I can't stress how important OIS is on a phone camera. No matter what resolution it is, always look out for OIS otherwise photos in the dark will look bad and you will have to take a few photos to get a sharp picture. So much for that 'super sharp 64mp' on the a71.
There are also more minor upgrades such as a metal frame, thinner bezels (slightly but noticeable), a bit of water resistance as it has rubber water prevention things in the sim slots which isn't there on the a71.