Plan expiration needs to be triggered. So you either need to visit the backend of CBSubs often, configure it to expire subscriptions on frontend, or setup a CRON task to regularly run the expiration check. This is explained and configured in CBSubs > Settings > Global. Note a subscription does not truly expire until the grace period has ended so if you've configured a grace period be sure you're checking back after that has ended.

As for integer vs text with decimals that should work fine since it type casts to float not integer so decimals should work. I do not recommend using a Text field type for this though use a Decimal Number field type, which will store in the database as float instead of text.

Then my guess is there's a condition problem in the auto action since it's responsible for doing the automatic renewal.

www.joomlapolis.com/forum/professional-members-support/245893-wallet-points-for-cb-subs-automation?start=0#334088

That would be Condition 3. It's possible the CBSubs Fields subtracting points is happening after CB Auto Actions. They both act on the same onCPayUserStateChange trigger so that's possible. Edit your auto action then under Parameters tab set the following and see if that resolves it.

Reload User: Yes

If still not working try moving the management of that field to CB Auto Actions as well then you can control the order of them executing. The below should work fine.

Global
Triggers: onCPayUserStateChange
Type: Field
User: Automatic
Access: Everybody
Conditions
Condition 1
Field: Custom > Value
Custom Value: [var3]
Operator: Equal To
Value: PLAN_ID_HERE
Condition 2
Field: Custom > Value
Custom Value: [var2]
Operator: Equal To
Value: X
Action
Field: SELECT_POINTS_FIELD_HERE
Operator: Subtract (Field = Field - Value)
Value: POINTS_COST_HERE

This should be ran before the renewal auto action so be sure the order is correct.