Its a difficult one, but its sometimes a matter of finding the right FF programme for you I think.
I booked a trip to Australia for a friends wedding and flying with QF, I took out a FF account with them, I too figured I'd get a load of points. I got 22137 miles for my first trip. With QF I have to do 4 flights a year on them and the points roll on year after year without expiring. It is a bit limiting especially now they've gone from having HKG, SIN and BKK stopovers (or options) to DXB, but I go to Australia every year at low season and pay a fare less than my work colleagues are paying to go to the US in the summer. My points have been ticking over, I sometimes pick up points for the programme from my hotel bookings or tours too, not just in Australia but anywhere I visit. Since LHR is my home airport, a large number of my flights are on BA (sometimes IB/AY) so it keeps the points ticking over. Then I found I'd gone up to a Silver member, so started to earn bonus points and now six years on, a lot of travelling later, I'm a Gold member and I will shortly have enough points for a first class return to Australia on QF.
I'm not a business traveller, I'm what I call a privately funded flyer! I travel discount economy 99% of the time.
I also started collecting points with AF, SK and LH. The SK and LH were probably a waste of time for me personally, as they are both Star Alliance, but I've learnt from that. I chose them as they were carriers I would potentially fly on, on a regular basis. However since my primary loyalty lies with the One World carriers, I found I travelled less with LH or SK for example, if BA were cheaper, but flying with LX and SN, would again keep them ticking over slowly. But annoying perhaps, the points do drop off from the Miles and More programme after a while if you don't use them. If you can't collect enough points in the meantime to use them, they are in effect wasted. However you can sometimes spend points in others way perhaps, buying something, putting them towards a part payment of a fare, an upgrade etc., so they may not be entirely a waste of time. For example I have a points card for purchases I make at LHR (ie car parking etc), and I can convert them to LH Miles and More so I might get enough for a flight, failing than an upgrade.
I'm not familiar with the Kris programme, but you will be able to collect points from other Star carriers, so as one of the other posts said, they're free to collect so why not do it and see what you end up with. Obviously these systems are not meant to give flights away too freely and you have to work at it, but you can also work the system to your advantage too, and of course if you can go up a tier or two the benefits help and it fuels the loyalty too, which of course is the main aim in the first place. See how you get on.