I have to believe MyPoints and their new video "supplier" has coded each individual video with a particular number that may reset at 0000 PDT/PST (0300 EDT/EST) every day...
So it is 1x per video / day (but you can click "load more videos" to get at the ones from yesterday and those would count). The only problem is that now you don't know how long they are (so you could "pick and choose" the shortest for not wasting your time) until they start to play. Getting any good amount of points takes quite a while (like the 50 I did once, that took close to 3 hours among 2 sittings)...
Also Ipsos has solved some of their problems with the surveys (there's one in particular that keeps getting stuck) and get to the 5 points almost soon enough. That mostly has involved working with other survey companies like Opinions Now and Samplicio...