The two straight stitch only machines I use all the time have knee lift and I never use them. They just get in my way, so I don't like them.

My Janome 6600 has a knee lift which I really like, but when I bought it I didn't know there were bobbin sensors on some machines also. I do all my own FMQ and a sensor would really be useful. Don't know if I want to get a different machine at this time in my life. Really like what I have.

I have knee lift and tried to get use to using it. It never became a convenience to me. The lever was in my way and caused annoyance.

One of my machines has it. I also sew on vintage machines in a cabinet that have the controller in the case and there is a thing to press my knee against. So sometimes I get confused with the different ones. Mostly I don't use it. It isn't a "must have" for me.

i learned on machines like that. after all these decades, when i have the knee lift hooked up, i automatically try to use it as the power control. it's sooooo much fun [not] when the foot goes up while i'm still sewing.

most of them are not positioned properly for me, either.
the lever is too far away from my leg.
i either have to scooch over so my view is distorted or i have to swing my knee waaaay out like i was on some crazy exercise equipment.

happy for those who have and love them.
mine are all tucked away where they can do no harm. lol

i know! Annoying for sure to get them confused.

My mothers Singer machine had a knee lift. My Janome used for piecing came with a knee lift, but when we dropped it into a table so that it was flush with the table top, husband forgot to mark a hole to put the knee bar into. Using the foot pedal works for me.

I have it on both my Bernina and love it!
You get used to what you have...

I'm getting ready to do so serious chain piecing and I'm going to give the knee lift a try.

I learned to sew on 60's singers and like above, it always was the go forward mechanism.That is a hard instinct to break.
I finally did on my Janome's but the lift is way too far left, to compensate I added two layers of pool noodle to the shaft.

I never use it now so took it off about a year ago. It was wonderful for machine applique though.
The bobbin thread low sensor, comes on (to my knowledge) the machines that stitch out motifs.Having an embroidery module adds a Lot to the cost of a machine and go off way too early (again and again) for patchwork.