Unless you have a small library of games and no backlog keep it. If not sell it.

I say, make your cousins happy...
They will appreciate it, you'll be sure that it's being used the best way possible, and if ever you need to really play that one game, you can always borrow it.

If you don't play it, then sell it.

I'd keep it and store it in a safe place.

I'm never going to sell my ps3. I got a ps4 on release, but I love my ps3 too much to ever get rid of it.

1-If you need the money sell it.
2-You can lend it to your family if you are nice.

BUT mainly keep it. I never sell anything as when I buy something I dont intend to ever sell it as I would lose money in the long run (that is why I buy things on sale and such).
PLUS youll regret not being able to play PS3 games at one stage or another.

Sell PS3 and buy two PS2s.

You will regret selling it down the road, I guarantee it. Never sell consoles, you may not use it now, but one day you will want to come back to a great game and will regret not having it.

Whatever u wanna do just don't sell it! PS3 emulation will take years to happen and for that u need a very very bad ass PC, its not gonna happen on PS4, using PS now is not comforting and u don't wanna rent the games and stream them when u can easily play the games locally and offline.

Just don't sell it buddy, u gonna need it to play some games that u miss from last gen and believe me it will happen!

I still use my PS2.